Tip drill (defensive): a U.S. football drill for the defensive squad, consisting of a tipped pass and defensive secondary scrambling for the tipped ball. They must catch the ball before it hits the ground. If they do, it's called an interception. Gets linebackers, cornerbacks, safetys used to the chaos that results when a ball is tipped into the air and everybody is vying for the catch.
Also usually involves pain, because the jostling of bodies in pursuit of the ball is usually done at very fast speeds. Defensive secondary players have their eyes focussed on the falling ball and not so much on other players. It is not infrequent that one defensive player will hurt his own teammate in pursuit of the ball.
A quarterback throws a low pass to the tips of a lineman's fingers. The pass is deflected in a random direction, usually up and to the left or right.
Players in defensive secondary skill positions stand on the other side of the lineman and practice their reflexes catching the errant ball with a very few milliseconds to decide which way to run in order to catch the tipped pass.
Tip drill (offensive): The receiver corps practices end-of-game Hail Mary tip drills. Three receivers will purposely tip the ball in a set direction so that a fourth receiver can catch it. Hail Mary passes, like so many other simple acts in American football, look chaotic and disorganized to the untrained eye, but in reality have been practiced over and over again on the practice field.
Inspired by Sekicho's recently written tipdrill, which means something very very different. Orange Julius reminded me of the offensive tip drill.