Well with my ex we kissed for ages and I got on top of him fully clothed and started grinding while still kissing him. He was really hard. He started touching my breasts and putting his hands down my pants. He had to leave soon for work so when he took his jeans off to put his work pants on he showed me the wet mark in his boxers from pre-cum and then on his penis, I licked it off. I suppose it's just when a guy gets really really horny.