1a)Launching a person into the air, through a well-placed kick, or uppercut, and then positioning yourself underneath them, squatting, sitting or in crab-walk position, with one knee fixed firmly upright, so that the recipient lands their Grundle directly on your knee.
1b)(also known as "Grundle Bomber - Jackhammer style") A grappling move, in which the one who performs the Grundle Bomber launches into the air with the recipient, turns them upside down, holds the recipient's Ankles, and places their foot(s) or knee(s) on the person's Grundle. This will cause them to land perpindicular to the ground on their head, while the one who is giving the Grundle Bomber lands with their foot(s) or knee(s) on the recipient's grundle, usually causing the recipient to split in half.
2)Placing an explosive device in the pants or underwear of the recipient, in the grundle area, and causing it to detonate while they are being worn. Can be used in conjunction with definition 1.
3)Using one's Grundle to physically attack, As seen in the Jumping/butt-slam move in the popular video game "Street Fighter 2" by E. Honda.
When referring to the action, or the person performing the action it is still referred to as "Grundle Bomber". The "er" suffix is only removed when the tense is changed.
Declan:"Who gave you the Grundle Bomber?"
Jon:"It was that Damn giant Robot."
Declan:"Oh yeah, I know that guy, he's SUCH a freaking Grundle Bomber."
Jon:"Yeah, tell me about it"
Declan: "He would give his Grandmother a Grundle bomber if he wanted to, he doesnt even care."