It happens to me a couple of times a year.  

For whatever reason the my thumb or thumbhole seems very slick.  I have read it is because of low humidity, the skin on the thumb gets dry.  

Last week, I felt this problem coming on in warmup.  In the third frame, my timing was a little early and the ball slipped off my thumb, dropped on the approach behind me and went in the ditch about halfway down the lane.  Naturally I grabbed the next shot and put the ball on the beak.  I was fried for the rest of the night.  

This is not a result of the thumb shrinking, tape can fix that.  I usually have to worry more about a clean release than slipping off the thumb.

Solutions?  I have changed thumb slugs to softer ones.  White tape in the front of the thumbhole only makes me grab at the bottom.  Cupping the wrist through release helps some, but causes inconsistent results downlane.  

This has happened to me for years and I haven't figured it out yet.
--------------------
Obama 2008: "Transparency, C-span, Openness, Post Racial, Bipartisanship, no Earmarks, fiscal prudence, no taxes on the middle class, close Gitmo."
Obama 2009: "You fools really didn''t believe all that sh## did you?"

When written down, this sounds like a lot of work, but it takes one minute before practice each night to do...

I use white tape in the front of the thumbhole, wear Vise Hada patch on the back of my thumb, and put a light coating of New Skin or Skin Patch (or whatever you want to call glorified clear nail polish) on the sides of my thumb. I fine-tune the feel with slick black tape on the back and sides of the thumb (since my thumbhole is ovaled, and the sides of my thumb tend to swell and shrink more than the front and back do). I also blow into my thumbhole to create a consistent level of moisture before every shot. I replace the tape every 3-6 games, and occasionally clean the thumb slug with alcohol.

The result? My thumb's texture and feel is very predictable and consistent, even if my thumb has a habit of swelling and shrinking and sweating and all that annoying stuff!

Thanks, guys.

I haven't used resin because I when I tried in the past, it was too grabby and my problems usually are getting a clean release rather than the ball dropping off.  

I will try the other stuff too.  This problem usually results in a series in the 4's or low 5's, so its a big one I need to solve.
--------------------
Obama 2008: "Transparency, C-span, Openness, Post Racial, Bipartisanship, no Earmarks, fiscal prudence, no taxes on the middle class, close Gitmo."
Obama 2009: "You fools really didn't believe all that sh## did you?"

I normally rough up my thumb hole a bit when I get the ball (partially due to my thumbs coming from a mold and quick plug is slick) and then blow in the thumb hole. I don't have issues with it and credit a lot to as mentioned the consistent moisture from blowing in the thumb hole.
--------------------
BowlingChat.net