Sister In Laws Lover

My brother in law was upset and asked if I’d do him a favor. He said he was sure his wife, my sister, was cheating on him and asked if I’d check up on her. I told him I would but what I didn’t tell him was that he was right. She was cheating but it was with me. My sister is a hot piece of ass. 36 C tits with nice nipples, flat stomach and an ass to die for. She’s been sucking my cock since we were teenagers and loves 69ing. Her pussy is always wet and ready for cock. I’ve never fucked her tight asshole but I always make sure to tongue fuck it until she cums. I know I’ve ate a few of her husband’s loads from her pussy and not going to complain about it. Truth is I’d suck his cock if he’d ask me. Anyway, I told her what he asked and all she said was she wasn’t going to stop having sex with me. I just hope my wife doesn’t ask why I spend so much time with my sister.