Lily caught her brother jerking off and helped a little

I wanted to have a quick wince while my sister is in her room getting dressed for a date. I take off my panties, close my eyes and imagining a naked classmate in front of me, I start to masturbate. Suddenly, Lily wants to use the toilet and she is in her underwear, she walks through my room. Naturally, she catches me jerking off, and since my eyes were closed, I did not see how she sat next to me on the sofa. Sister briefly looked at my handjob and bent down, took my cock in her mouth. "Oh my God, what are you doing?" I say opening my eyes, but Lily didn't want to let my dick out of her mouth and continued to suck it...