When it comes to kissing I feel like they wouldn't, unless BH used the gesture to publicly display his ownership of Flug. Flug generally hates it, because he wants to enjoy it but can't since he barely feels it and knows why BH does it.
BH never lifts the bag; he prefers Flug doesn't enjoy it. ...The bag does get lifted once, but it's initiated by Flug and he never does it again.