Rule References:
KICKING TEAM PLAYER OUT OF BOUNDS
Article 3 A player of the kicking team, who has been out of bounds, may not touch or recover a scrimmage kick beyond the line of scrimmage until it has been touched by a kicking team player who has not been out of bounds, or until it has been touched by a player of the receiving team beyond the line.
Note: If a player touches or recovers the ball before he has re-established himself inbounds, the ball is out of bounds at the spot of the touch, and there is no foul.
Penalty: For illegal touching of a scrimmage kick: Loss of five yards. If the illegal touching is inside the receiver’s five-yard line, in addition to the other specified options, the receiving team may elect to take a touchback.
In addition:
KICKING TEAM PLAYER VOLUNTARILY OUT OF BOUNDS
Article 5 During a punt that crosses the line of scrimmage, and prior to a change of possession, it is a foul if a kicking team player goes out of bounds voluntarily (without being contacted) prior to the end of the kick.
OFFICIAL NFL PLAYING RULES 5 If a member of the kicking team is forced out of bounds, or goes out of bounds voluntarily, and does not attempt to return inbounds in a reasonable amount of time, it is a foul for Unsportsmanlike Conduct. See 12-3-1-(t).
Penalty: Loss of five yards.