What's this feeling ?

It's super hard to describe but ima do my best... 
I'm 36w4d. My son is head down, pretty low for the most part. At times I can be standing there or even laying down and a zing goes in my crotch area. NOT comfortable either, very unpleasant feeling then it goes away. Maybe he's hitting my cervix? I'm not sure how that's supposed to feel. I don't think it's lightning crotch- doesn't feel like that..
What do you think it could be???