What you should have known

Written for sherlockbbc_fic. Prompt: Jim/Mycroft, bukkake (non-con). Jim wanted Mycroft for a very long time, but when he finally manages to capture him he finds he can't quite bring himself to violate 'the iceman'. Still, that doesn't stop him from tying Mycroft to his bed and masturbating until he ejaculates all over him. Repeatedly. Bonus: Mycroft keeps his composure through all this even though he is absolutely horrified. Unfortunately, that gets Jim even more excited.