If it were me, I'd probably go with "bottom bicurious". If looking more to be used, then probably "sub". If it's established that he enjoys it, then remove the "curious" part.
When we were talking to a bi male friend, I used the term "orally bicurious" to describe where I was at the time. I think context is important, as is the reason of looking for a label.
When we were talking to a bi male friend, I used the term "orally bicurious" to describe where I was at the time. I think context is important, as is the reason of looking for a label.