Possibly a thumb slug....and drill that, no plug used. But once anything is drilled it is tough to put the material back.

Easiest way to take up space, without plugging and redrilling is lining the hole with strips of velcro rug. Not the hook side (male). The catch or fabric side(female). Usually when I do it right, it makes for a real comfortable, yet snug fit, that still gives a good clean release, without irritating your thumb. I place the rugs towards the back of my thumb, leaving the pad area clear, if I should still want to add tape.

I use the hook side when i want to have and create friction, on the pad side of my thumb. This aids my muscle memory, and reminds me when I've released the ball correctly. Just a couple of things I 've learned over the years.

Scott--Try Ron Clifton's Magic Carpet.  I gave Rob a piece of years back and not sure if he still has it or not or let me know and you can have one of mine.  I use three different sized Vise IT thumbs and use MC on the back and one piece of 3/4" wide textured white in the front.   Change IT's for best fit and as thumb goes up or down just change the IT rather than fiddling with tape.

I have been a devout MC user for 10+ years.  They run $2/ea buy 10 at a time and last about 50-60 games for me before worn out.  http://www.bowl4fun.com/magiccarpet/magiccarpet.htm

Easiest way to take up space, without plugging and redrilling is lining the hole with strips of velcro rug. Not the hook side (male). The catch or fabric side(female). Usually when I do it right, it makes for a real comfortable, yet snug fit, that still gives a good clean release, without irritating your thumb. I place the rugs towards the back of my thumb, leaving the pad area clear, if I should still want to add tape.

I use the hook side when i want to have and create friction, on the pad side of my thumb. This aids my muscle memory, and reminds me when I've released the ball correctly. Just a couple of things I 've learned over the years.

+1