Ironically, when Lisa looked up at the sight of their mother catching them in the act, she still had a finger deep in her sister's sopping wet cunt and made no effort to remove it even as she was tongue stumbling over her words.<br/><br/>"Yeah.....it's just like....uh, like Cassie said, Mom!....we were kissing...I mean, I was teaching her to...."<br/>Like her sister, Lisa followed Cassie's eyes to their mother who still remained leaning up against the open doorway.  They've both seen their mom nude and semi nude often during their early years but not lately.  For some reason, the looked sexy....very sexy, in fact.  A thought quickly ran through Lisa's mind.  Was it wrong to think about what their mother's body looked like under her skirt?<br/>Right now however, it was her sister that was still laying next to her, that warm soft supple body, those creamy titties.  Whatever might have been considered taboo right now seemed almost natural to Lisa.  She glanced up once more....if their mother wasn't going to interferre then she would continue.<br/>Lisa began sucking on her sister's nipples, finger fucking her again, coaxing one more orgasm....