getting hit (in a video game) by a grenade that sticks to the player (examples would be Halo's plasma grenade and Gears of war's "bolo" grenade), getting "tagged" usually ends in dieing, because most grenades kill in one hit.
used directly in "Gears of war" where you can "tag" your enemy by melee
ing with the grenade equipped
in "Halo" tagging can be done with the plasma grenade by throwing the grenade so that it hits the enemy and sticks.
Getting "tagged" is not very fun, because you know you can't do a thing about it.
alternate sayings: "tag" "tagging" "taggers" "tag whore/nade whore"