First, Gohan kicks his opponent a few times, he then beats them up and kicks them to one side. He holds one hand with the other supporting it upward in a fashion similar to the Explosive Demon Wave and, as he shouts "I've had enough!", he forms an energy sphere with excess energy releasing off of it in the form of medium-sized energy rings. Finally, Gohan brings his hands forward and fires a powerful yellow energy wave with a large energy sphere at the end at the opponent, inflicting a high amount of damage.
Gohan uses this attack against Frieza in his third form after saving Piccolo from the tyrant's Crazy Finger Beam. Frieza catches the attack, but when Gohan charges his full power into the Wild Rush Blaster, Frieza is knocked backwards into the ground. At the last minute, Frieza gathers enough strength to throw the attack back at Gohan. However, before the Full Power Masenko is about to hit Gohan, Piccolo saves the young Saiyan by destroying the attack with an energy blast, causing it to explode and rain thousands of energy spheres across Namek.
Appearances in games
It appears as Kid Gohan's Ultimate Blast in Dragon Ball Z: Budokai Tenkaichi 2 and Dragon Ball Z: Budokai Tenkaichi 3, under the name Bakuretsu Ranma. In Budokai Tenkaichi 2, instead of the Full Power Masenko, Gohan fires a Gekiretsu Madan, like he does after the rush he uses against Frieza in the manga/anime (technique called Burst Rush in Dragon Ball Z: Attack of the Saiyans).
It is named Full Power Masenko (フルパワー魔閃光, lit. Full Power Demon Glint) in Dragon Ball Z: Supersonic Warriors and Dragon Ball Z: Battle of Z, and Raging Rush in Dragon Ball Z: Supersonic Warriors 2 (as Super Saiyan 2 Gohan's Ultimate K.O.).
"Fires a barrage of powerful Ki Blasts and a Ki Wave. There is a long period of vulnerability after this attack."
— Dragon Ball Xenoverse 2 Tutorial description
In Dragon Ball Xenoverse 2, this technique again appears under the name Explosive Assault and is performed in the same manner as it was in Xenoverse. It appears as Kid Gohan's Ultimate Skill which the Future Warrior (Xenoverse 2) can learn by completing School Quest: Lesson 3 of Kid Gohan's Training.
In Dragon Ball Fusions, Full Power Masenko appears as a stronger variation of the Masenko that is even stronger than Super Masenko and lacks the rush entirely. This version of Full Power Masenko can be used as a Special Move by Gohan (Young), SSJ Gohan (Young), Gohan (Teen), Future Trunks (DBZ), Future Trunks (Super), Super Saiyan Future Trunks (Super), Coohan, EX Gohanks, EX Trunks, Kallohan, Krigohan, Moolin, and many others.