Tight thumbs

[JDrummys]

Lately, I'm finding it hard to relax my right thumb when trying to play fast, and my thumb joint tends to cramp up from squeezing the stick too hard- and I know this is slowing my playing- but I can't seem to relax it!- I even use the Weckl grip where he says to use the thumb and the middle finger as the fulcrum (says it makes for a looser fulcrum)...Does anyone have any suggestions to help relax this thumb grip?