At some point Sebastian and Blaine have to have sex with Kurt and someone (from the government?) has to check him over. I think they try something and Sebastian has to go in to the room Kurt is in and kick them out. I remember Kurt being reluctant to have sex with them and was sort of scared about it.
I'm not sure if the fic was finished or not.
This was a while back, but if you know what fic this is I'll be very grateful if you can help me out! Thank you. :)