So, when I lay on my back on the floor with my knees up, and I lift of my pelvis/hip area, there is a pop in my lower…

So, when I lay on my back on the floor with my knees up, and I lift of my pelvis/hip area, there is a pop in my lower spine, right above the tail bone and right below my hips. It feels like my spine is almost disconnected and popping in and out of socket.. it's not painful though. Anyone else have this issue?