To lightly rub the tips of your fingers across someone's back (or anywhere else for that matter) to produce a slight tickle that feels very relaxing and can put you to sleep.
Guy 1: I was having a hard time sleeping, so my girlfriend gave me tickies. It was the most relaxing thing ever.
an occasionally violent game created by Anna Davis that always results in one kid getting injured.
how to play:
one person is chosen to be the "tackmaster" everybody else lies face down on the grass apart from each other. the tackmaster chooses the person to be TACKLED. the last person to get tackled is charged at by everybody