Somebody you generally trust or would rely upon. If you were in a foxhole, taking grenades, you would want this person to be with you.
1 I told my co-worker not to tell anybody that I was sneaking out for a bit to go meet up with this chick but he ended up ratting me out. He's not a foxhole guy.
v: Short for going Genitals to Genitals
Can be used in many contexts mostly in a joking or story telling manner. Can be sexual or non sexual.
1. So you go geni to geni with that girl you met last night?
2. You looked like you were going geni to geni with that dude when you spotted him doing squats.