It's a bottom's obligation to clean off the tops cock....hell what would happen if the top goes home to his wife, or hubby, and has another guys ass smell on his cock?  I always clean the tops cock off, and love it when it's still dripping with cum.  And any bottom who cleans mine off after I take him, makes me feel like he has enjoyed the ride, and is thanking me for it.  I did recently have a friend get fucked by my hubby, and then I ate my hubbies load out of his ass, before fucking him myself.  Why waste any load.