While a trooper in the First Order, Finn always ached for a hug, or a pat on the back, a hand shake -- anything touch related. He loved the impersonal physical examinations and The Hunger Games/Battle Royale-esque wrestling training matches because that was the only time the troopers weren't wearing armor and someone touched him.

Poe touches Finn a lot. Pats on the back. Fingers grazing when Poe passes him something. Warm hugs and embraces. Keeps his hands in place and envelopes him from behind when teaching him how to fly an X-Wing, use this weapon, figure out this equipment, etc.

bonus
- Poe's shamelessly flirting. Finn pines away, oblivious, thinks this is just how friends act outside of the First Order