Asklemmy

This was taught to me,

Snuggle and cuddle. Tell the person you want to cuddle, means to curl up together under a blanket and watch a movie. Tell the person snuggle when you want to fuck (but your being discreet). And if your hair looks a little messed up or someone asks what y'all been doing... snuggling 🥰

Pig-Latin but very fast. Decades of practice.

Spanish

Swiss-German is a pretty good secret language.

Perhaps more useful is to silently make your mouth into an "o" like you're saying "go" if you want to go, or a line like you're saying "stay" if you want to stay.

Nice try.

I wouldn't call either of these particularly secret, but whatever, they're fun.

Excess material = a very large shit, often multiple shits.

Trip insurance = using the bathroom before getting in the car, whether it's needed or not. I came up with this one as a child, and it's now in widespread use in my extended family, especially with the nieces and nephews.

Very rudimentary Japanese, or incredibly elaborate/old Englishy stylized speech

English.

We have a Darmok and Jalad at Tenagra style system where we reference memorable past events.

We have a code for when we're ready to leave a party. One of us will go to the other and do the finger walking up the other's arm. This means "I want to go home."

My AuDHD self went and married another ADHD person, and we are both full of little non-verbal cues we give each other, and they range from Significant Glances to discreet groping. We communicate well (and I 100% think the reason we get along so well is because we communicate) and non-verbal is just part of it.

When we travel: speak japanese. Else, we've been together enough to know each other pretty well and often don't need to say much aloud to communicate something