I regularly tickle my wife, who is 60 (older than me) and she is pretty ticklish but she'd never let me tie her up and do it for a while - my greatest joy, though, is to go a dungeon and put a girl 18 to 25 or so in full restraint and tickle her for an hour or two - either lightly or intensely - it's just such a different feel to have a laughing, screaming, squirming, struggling, sweating young girl doing all she can to get away while I tickle her - and, yes, I do use a safeword - I don't want to hurt anyone.