Shiro/Lance get into shenanigans and have to fuck to get it out of their system
http://archiveofourown.org/works/12234321
Shiro/Keith have to do a weird sex ritual to appease pissed off aliens
http://archiveofourown.org/works/9643814
Keith is assigned to milk literal titcow Shiro and his buddy Lance
http://archiveofourown.org/works/11293902/chapters/25267353

Shiro/Sendak boning
http://archiveofourown.org/series/522955