DD did when she was little. She was always walking up to us & pulling up her shirt giggling (before she could talk.) She would often ask us to tickle her once she could talk - I think it stopped at about age 8. . . . . although I know she still doesn't say "Stop!" if her brother catches her off guard.
I have to admit she's the only person I know that doesn't eventually yell "Stop!" & get mad, though.