Raiden I had the same thing and my own was due to prolonged (and I mean prolonged) periods of sitting at work. And when I felt that numbness hit my arse, I would simply just get up for a few seconds and sit right back down. Stupid, stupid mistake.
I took me a very short time to mess myself up and over one year to fix it.
I started to perform every morning without fail rope and band stretches. You lay on your back but the band or rope on your foot. Put your foot in the air and stretch it toward your chest. And at first I couldn't stretch worth crap, but little by little it got better.
Then I also started to do glute bridge exercises at the gym. And even though it looked weird sticking your privates into the air with a bar across your hips; the exercise helped a lot.
Another thing that I did was kickbacks on a machine. That's the machine that most woman use to tighten their bottoms. And believe me, that was a humble experience because I felt like such a wimp.
And the thing that upset me the most was that my powerlifting went down the toilet. Hell, I could even feel my bad glute go numb when benching. So forget about squatting or deadlifting.
But now, I don't sit for long periods. I stretch every day in the morning and afternoon. Continue on with my "weird" exercises at the gym and have been able to get back to my powerlifting
Hope this helps...