She will purposely stop to get you to sqeeze her with your legs. The harder you squeeze, the more she squirts and enjoys it. Sadiescreek
Im sorry I know this is frustrating for you but I'm laughing my butt of reading this!!!!
I only know part of your frustration because I have a 12 hand pony mare that NEVER showed any signs of heat even when with my gelding for years. Then I bought a nice big handsome dark QH and she thought he was a FIIIINNNE LOOKING MAN! It doesn't matter what time of year it is or what day, she will walk up to him, tail swish and squirt!!!!