Don't use your pinkie or any finger. Use the meat of your hand to hit the control key.

This works especially well on an IBM Model M because there's nothing in the vicinity of either the left or right ctrl, you just chop your palm down and can't go wrong. I could also pretty reliably M-x in one hit by flipping my left hand over, curling my pinkie finger, and hitting the keys with the knuckles. On more crowded keyboards I remap ctrl:nocaps and use thumb and forefinger for M-x. I actually deliberately got rid of my Model M to teach myself to do it this objectively worse way, because context switching between my docked workstation setup and laptop keyboard on the go was difficult. If only someone would make a laptop with a proper keyboard...