Believe me, honey, I told your sister she can't suck me off!!

What a mess you've gotten yourself into, man. You can't have such a nice girlfriend and at the slightest chance you'll get involved with her sister and on top of that, she's at home, damn it. It's normal for her to catch you like this and you can't tell her what you said, that it's her sister's fault because she wanted to suck you off and you told her no, that it's not right... now let's see how you get out of this because you've gotten yourself into so much trouble and all for a blowjob, damn it...