um.. popping noise when baby moves..?

okay so seems like my little girl is becoming more active as the days go by..   but welli dont know if her hand or foot hits like my side and it makes a popping sound like if you were cracking your knuckles or something like that and well too me is funny it happens like frequently... ive asked people but they just look at me like im weird   but has anyone experienced this or knows what im talking about?  

Its just your bones cracking because your hips are spreading apart.
mine did that all the time =).

I know im not that far..only 18 weeks
but i swear when I was laying down to sleep i felt a kick and heard popping
my husband thought he herd it too!