As far as I can see, your sister has given no indication that she is interested in having sex with you. You saw her virtually naked, and you have become extremely sexually aroused by this. Nothing in your post suggests that she feels the same sexual attraction towards you, as you feel towards her. The fact that she was trying to cover herself from your stair would suggest that she was surprised, and probably embarrassed.
Of course, this is a natural reaction to being caught unawares, and anybody would react in the same way, even with somebody that they found sexually attractive. But you are jumping the gun somewhat. Your sister may have seen your erection rising in your shorts, but you don't know what she thought on seeing such a thing. There might even be part of her mind that wonders what it would look like if you hadn't been wearing the shorts in the first place. I assume, because you haven't said anything about this in your post, that there is no prior history of you and your sister being in any kind of intimate situation together. So the problem you face, if you really do wish to take this further than just a masturbatory fantasy, is finding out how she feels about incest, and more specifically, whether an incestuous relationship with you would be something that she would want to enter into.
Depending on where in the world you live, incest may be illegal, or it may be illegal but tolerated amongst consenting adults, or it may be regarded as nothing more than a social taboo. In countries like India, |Russia, and Spain, incest is not illegal as long as those involved are at least the age of consent. In Spain, that means anyone who is over the age of 14. As far as I can remember, incest is tolerated in some other European countries, such as France and Germany, although I do think there are laws on the statute books. In practice, these countries do nothing about it if those involved are above the age of consent, and consenting participants. As you and your sister are both in your 40s, then the age of consent is not applicable. You haven't stated where you live, but the fact that you use the term wanking would suggest that you live in the UK (as" wanking" is a favourite expression to describe masturbation throughout the United Kingdom, but not used in many other countries, except perhaps Australia and New Zealand). To the best of my knowledge, incest is illegal in the UK, and if brought to the attention of the authorities, it will be prosecuted. My own personal opinion is at the things that people do with each other should never be illegal if those involved are consenting freely to what is going on, but that's only my opinion, and should not be taken as a recommendation to break the law.
So, how do you find out when your sister's view of incest really is? As you need to establish this before you take any further steps. You could try looking in the newspapers articles about incest, talk to her about it in a conversation, and see what her reaction is. You need to bear in mind a couple of things so, as people may say one thing, but feel completely different about it privately. When it comes to taboo like incest, most people would publicly deny that the idea has any appeal to them whatsoever, yet at the same time, in their secret fantasies, it might be something they find tremendously exciting. So that is a tricky question to pose. You also have to consider how you would even broach the subject, given that you and your sister do not live together. It's not like you can just pick up the phone and start having a conversation about incest, even if it was splashed across the headlines of the daily newspaper. You would have to have a reason for bringing the subject up in the first place, and then you could possibly gauge her reaction. But the thing is, even if she has no objections to an incestuous relationship, it doesn't necessarily mean that she wants one herself. I suppose you could use the situation where you walked in on her unexpectedly and make some jokey references to how fanciable she looked, and see how she reacts to that. Depending on what she replies, you might be able to take the conversation further, and find out how she feels.
You could, I suppose, try asking her out right, and see how she reacts. Don't be too surprised if she slaps you round the face so!!!
The last thing I would say is this: fantasising about having sex with your sister is one thing, making it fantasy turn into a reality is another thing entirely. I'm not saying whether it's right or wrong, only you can decide for that, you and your sister both. But you have to understand that if you did engage in a sexual relationship with her, where both of you are consenting to this, you would change the dynamics between yourself and your sister, yourself and your brother-in-law, and yourself and your wife. And your sister would be doing the same. The consequences of it, while only the two of you would know what that could result in. I actually know of to brother and sister relationships, where they live as husband-and-wife, unbeknown to all those around them, except very few very close friends. One couple even as to beautiful, perfectly normal, children. These are some of the consequences of incest. There are other consequences, and some of them can be really dark, so consider carefully before even embarking on anything further.
Good luck,
Salma
Of course, this is a natural reaction to being caught unawares, and anybody would react in the same way, even with somebody that they found sexually attractive. But you are jumping the gun somewhat. Your sister may have seen your erection rising in your shorts, but you don't know what she thought on seeing such a thing. There might even be part of her mind that wonders what it would look like if you hadn't been wearing the shorts in the first place. I assume, because you haven't said anything about this in your post, that there is no prior history of you and your sister being in any kind of intimate situation together. So the problem you face, if you really do wish to take this further than just a masturbatory fantasy, is finding out how she feels about incest, and more specifically, whether an incestuous relationship with you would be something that she would want to enter into.
Depending on where in the world you live, incest may be illegal, or it may be illegal but tolerated amongst consenting adults, or it may be regarded as nothing more than a social taboo. In countries like India, |Russia, and Spain, incest is not illegal as long as those involved are at least the age of consent. In Spain, that means anyone who is over the age of 14. As far as I can remember, incest is tolerated in some other European countries, such as France and Germany, although I do think there are laws on the statute books. In practice, these countries do nothing about it if those involved are above the age of consent, and consenting participants. As you and your sister are both in your 40s, then the age of consent is not applicable. You haven't stated where you live, but the fact that you use the term wanking would suggest that you live in the UK (as" wanking" is a favourite expression to describe masturbation throughout the United Kingdom, but not used in many other countries, except perhaps Australia and New Zealand). To the best of my knowledge, incest is illegal in the UK, and if brought to the attention of the authorities, it will be prosecuted. My own personal opinion is at the things that people do with each other should never be illegal if those involved are consenting freely to what is going on, but that's only my opinion, and should not be taken as a recommendation to break the law.
So, how do you find out when your sister's view of incest really is? As you need to establish this before you take any further steps. You could try looking in the newspapers articles about incest, talk to her about it in a conversation, and see what her reaction is. You need to bear in mind a couple of things so, as people may say one thing, but feel completely different about it privately. When it comes to taboo like incest, most people would publicly deny that the idea has any appeal to them whatsoever, yet at the same time, in their secret fantasies, it might be something they find tremendously exciting. So that is a tricky question to pose. You also have to consider how you would even broach the subject, given that you and your sister do not live together. It's not like you can just pick up the phone and start having a conversation about incest, even if it was splashed across the headlines of the daily newspaper. You would have to have a reason for bringing the subject up in the first place, and then you could possibly gauge her reaction. But the thing is, even if she has no objections to an incestuous relationship, it doesn't necessarily mean that she wants one herself. I suppose you could use the situation where you walked in on her unexpectedly and make some jokey references to how fanciable she looked, and see how she reacts to that. Depending on what she replies, you might be able to take the conversation further, and find out how she feels.
You could, I suppose, try asking her out right, and see how she reacts. Don't be too surprised if she slaps you round the face so!!!
The last thing I would say is this: fantasising about having sex with your sister is one thing, making it fantasy turn into a reality is another thing entirely. I'm not saying whether it's right or wrong, only you can decide for that, you and your sister both. But you have to understand that if you did engage in a sexual relationship with her, where both of you are consenting to this, you would change the dynamics between yourself and your sister, yourself and your brother-in-law, and yourself and your wife. And your sister would be doing the same. The consequences of it, while only the two of you would know what that could result in. I actually know of to brother and sister relationships, where they live as husband-and-wife, unbeknown to all those around them, except very few very close friends. One couple even as to beautiful, perfectly normal, children. These are some of the consequences of incest. There are other consequences, and some of them can be really dark, so consider carefully before even embarking on anything further.
Good luck,
Salma