Loved reading this thread. It has made me cheerful!
If a song lyric can be worked into a conversation, it must be done. Similarly any emotion, can and will be expressed through the medium of modern dance.
Stealth bumming. If other person is bending over, silently creep up behind to the best of your ability and lean your crotch in, hands on hips and thrust Mr Bean style. Extra points if they don't notice. Especially extra points if you're in a public place. Then whisper 'stealth bum!' As creepily as you can at the earlier available opportunity.
Curtsy or bow/bended knee when bringing other person a snack/cup of tea/dinner.
The dogs are Mexican foul mouthed spies. They have conversations about the weird things humans do and have been sent to learn our ways before invading. Singing songs to them is the only way to abate their blood lust and stop them reporting us to their government. Their names/nicknames must be worked into the song.
If something weird happens (a cup falls over in another room etc) and upon investigation it turns out to be that the drying rack was simply stacked improperly it is your duty to shout "debunked!" (From a program called ghost adventures)
We have many one liners stolen from TV, including, if someone says "but at the end of the day" the only acceptable response is to say "you died!" (Alan partridge)
If there's a monster/someone ugly on TV "I didn't know you were in this DP!"
If one of us says "I'm just going to the loo" then the other has to get to the toilet before the other, I can't remember when we started weeing competitively but its stuck! Extra points if the other person is desperate for the loo.
It's nice to read about other people's little idiosyncrasies. Makes me feel like everyone is as odd as us!