Girl flashing her boobs
Post-hypnotic suggestions are commands you give to your partner while they're hypnotised which they then follow when they're awake.

These can be commands to become horny when you give them a particular signal, or to perform some act such as to flash you when you say a certain phrase.

The great thing about them is that they're instant whereas doing a full hypnosis session with your partner is going to take 15 minutes or more. If you both unexpectedly find yourself with some time, then a post-hypnotic suggestion - say for intense horniness - will start working as soon as you trigger it.
Sexy striptease

You can give your partner a post-hypnotic suggestion that when you play a certain song to them they'll stop whatever they're doing and get up and do a sexy striptease dance for you. You can elaborate this and also tell them particular moves you want them to make. Add icing on the cake by telling them that doing the striptease makes them very horny and the scene is set for much enjoyment by all.

They also don't need to remember that they've been "programmed" this way. When the music starts and they find themselves stripping, they'll be completely surprised.
Strip poker

Strip-poker is always easy to win if you hypnotise your partner and tell them that any hand you show them is a winning hand.