Loosing erection when starting to move waist

So I’ve noticed something about myself that I find quite interesting but can’t seem to find any answer to. When ever I have to do any sort of motion action using my waist, whether that being penetration or even masturbation, my penis seems to have to response to any stimuli and I loose my erection rather quickly especially when I have to be in an upright position. My erections are perfectly fine whenever I’m laying down and stroking it or getting ridden.

Like what could be the issue? Maybe a weak pelvic floor, tense pelvic floor or am I desensitising my penis by masturbation often. I’ve also noticed that I don’t get morning erections and usually have to touch myself to get hard. My T levels are on the higher spectrum and my libido seems to be quite fine as I think about sex all the time.

Does anyone have any suggestions? Or is anyone having similar issues aswell.

Have a similar thing where I feel like often the higher the rate of speed or more motion I am doing, the quicker i can lose it. If we are in a position where I am standing it doesn’t seem ti happen. Wonder if anyone else has this or knows why? Could it be a blood flow thing ?

Do you feel any sensation? I figured I loose it because I don’t have no feeling down there when I have to move my body. If she’s doing all the movement then I’m totally fine. I’m suspecting it’s a pelvic floor issues. Might talk to a specialist and see what they say and I’ll reply back to you on here.