Comment on A Quick Bath by Neko-me
Dunno, but Twilight did it with Dashie.
RD was smashing through a barn at the time, and moment's later she rainbow nuked it. Despite how she seems to be lazy in some of the episodes, I think she's undergone some sort of training regimen at some point to increase her body's tolerance towards pain, thus not making her indicative of any baseline from which to measure how much being held by your tail hurts in Equestria imho.
I agree, though I think holding by tail must be painful, though to a different degree for different ponies.
Yep! What he said.