How do you sleep with Whitney?

Playing as female (trans, transmod) character with Whitney as the main love interest, fucked at least two times but I want to sleep with him. As in, not sex, but actually sleeping together with him, have him coming to the orphanage then spending the night sleeping together, or coming to his house so I can sleep there. Uh. Is there any way to do this?

Also I've heard you can visit his uncle's house or something, where and how do you get the prompt to that event?