Implicating triangle_position → threesome
Link to implication

Reason:

A proper triangle position can only be done with 3 characters, hence the prefix "tri" (three).

If somehow it is not proper to implicate it to threesome, then implicate it to group/group sex

I think the problem would only arise in the case of an orgy but I'd be fine with an image being tagged with orgy threesome, like post #753217. (The actual three-only ones should not be orgies, imo)

It might still be triangle position with a 4th person also interacting, so it doesn't really work.

group_sex would probably work though.

Approved implication to group_sex