Hand technique is like anything else. Use it or lose it.
Before jumping into composing or recording, most mornings I’ll run through some sticking exercises, rudimental drumming, coordination patterns, and sight reading to keep in shape.
The above video features improvised flams and flam taps, and few other rudimentary bits. Traditional flams, especially in drum lines, are usually played with a firm military execution. I prefer the Steve Gadd approach where he injects feel into rudimental based grooves and fills.