Some couples/ friends might use a wink of the eye, maybe a ding tap, or the easy way and just text each other when they are ready to exit the building. After a few drinks with the hubby last night we came up with some amazing secret phrases to use at parties. Any of these will be completely unsuspecting of other part go-ers or hosts.
#1. I would like to play Scrabble on the porch, in the summer.
#2. Senator Palpatine is the Emperor.
#3. The Emperor wants to play Scrabble on Hoth.
#4. Hoth is said to be pleasant in the spring.
#5. The Black Knight always triumphs.
These are solid. Use a little 'wink. wink. nudge. nudge.' if you have to, but I don't think you'll need to.