Glad you brought this up - and glad to hear your recovering.
I get the tingling/numb feet and occasionally hands during sex also. Not all the time, but often. I have no idea what causes it, but my hunch is low blood pressure/low sodium. I also cramp really easily if I workout too hard or play sports etc. and I can't help but think they are related. So my bet is sodium, I am not sure though. I haven't looked into cortisol.
If you figure out what it is PLS post the solution. Thanks