Sex last night

My husband and I had sex last night we did it twice... And when I laid down maybe hour or so later I felt this weird little movement in my uterus didn't hurt or anything just felt a little weird, like butterflies flapping their wings really hard it wasn't in my stomach it was just in my uterus part... He kinda gave me the giggles. Does anyone know what that is or what it means... I'm not pregnant but I am trying to conceive... Hopefully it was his swimmers making their way to their home tell me what you guys think thank you