It was my first year at uni and whilst straight i've always liked looking at men nude in the gym showers or swimming pool. I'd joined the university gym club and was changing aftera session when another guy stripped off and went toward the shower - I joined him and saw his penis which was big (ish) and semi-erect with the end poking out beyond his foreskin. Needless to say he caught me peeking, smiled, and carried on. After, he asked me he could borrow my towel and of course I agreed. One thing quickly lead to another and we got into his car, drove to a quiet spot and I sucked him off. He was clearly experienced and took a while to cum- but when he did! Never did it again- but still think I missed a vocation.