Firefly, Jayne/Simon, clean
Simon was a stickler for cleanliness. It was one of his cornerstones in life as well as a doctor. That's just how it was.
Of course, Jayne wasn't much for cleanliness, and when the drunken hand for hire crooked his finger at him, Simon couldn't say no. Not even when Jayne ran his dirt crusted fingers through his hair or when Jayne's soiled clothes were tossed right on top of his fresh laundry. Not even when Jayne bounced right on Simon's newly washed sheets and belched something foul.
All Simon could focus on was the weight of Jayne's strong hands on him or the feel of their cocks sliding against one another's as Simon attempted to spread his legs wider in an attempt to get Jayne as close to him as possible. He just wanted a hard fucking and Jayne was the man for the job.
Besides, there was always sharing a shower later on.