How does your cg/partner know you are messing?

[StinkyBoy24]

I’ve always been pretty good at being discreet when I need. My position hardly changes and I don’t show my strain on my face. However, my old mommy used to know, even when I thought she couldn’t tell at all. She told me it was because I made slight grunting noises and my hand always subconsciously floated to my bottom. What about you?

[Three Rivers]

Usually I just stand still for a few seconds and maybe my facial expression, then sometimes it's the smell that's a dead giveaway.