Still the practice was improving my skills and I had a couple of sketches the professor wanted me to build on. Then a new model came walking in to our...third week class. All the guys, and several girls perked up because this model was a young trim co-ed. Then I had to do a double take as my eighteen-year-old freshman sister, Samantha, dropped her bathrobe.The stodgy old professor was up there pointing out how the light strikes her skin at certain angles. All I could see was the slope of her. Then she told me something that made my heart sink.“I think Beth has met someone new, Jeff.” my mother-in-law said.“What makes you think that?” I responded in my bravest voice.“Last night she asked if it was too soon for her to be interested in another man?” was her reply.She went on to tell me Beth had told her nothing specific, but from the conversation, she had figured that she had recently met someone. My heart sank and I felt sick to my stomach. I quickly made up an excuse and ended the. " Guess you can afford it after today, huh?" She chuckled, then gave the wad of bills I stuffed into my purse a disbelieving look. "If I could pull in tips like that, guy or not, I'd lobby with Eileen to keep me on as one of her permanent waitresses." God," I moaned with a put-on horrified expression, "Don't say that too loud. You might give the boss ideas that I wouldn't be able to deliver on." You did just fine today," Nadine grinned back, then put on her own coat. "How about. It wasn't bad at all, it kinda turned me on even more, knowing that I had just sucked my first cock and swallowed my first mouthful of cum. Just thinking about it put me over the edge, I shot my cum all over his floor. After we sat down for a while, and that first guilty feeling had passed, I asked him if he'd like to do this again. He happily agreed and said that he wanted to suck me off next time. He also asked if his older brother could join us next time, since they had been touching each.