My hubby likes to joke and say that if he looks over at me and sees me with my hand in the shape of a hand gun, he knows he is in trouble, and if he looks at me and i am acting like i am holding a shot gun he is in the dog house, and if i start to load the gun then he has to start planning his funeral.
Of course he jokes aobut this (because he really knows that if i get to the first gun he better stop whatever he is doing )
But seriously with us we have been married and together long enough to know each other's looks so we know when things needs to stop. But you are not always keeping eye contact the whole time............. so we both know to speak up if something is making us uncomfortable. We have bothhad to in the past step up and say something instead of just sitting there feeling weird.
But one point i would like to express is that no matter what the reason or the signal that you give your SO or they give you.......... ALL activity should stop....... and the one having to stop should not be angry with the stopper. There should be no blame there and everything needs to be talked about as soon as possible.
Ok off my soapbox now.
Hope this helps.