The act of dropping ones overly obese body on top of a victim.
It usually results in the unsuspecting victim receives 200+ pounds of sheer fat being brutally pushed on top of them. The one gumminating must also announce their attack whilst in midair, in the manner of "GUMMINATION".
While the Gummination can be used as a full contact hit, it has variations; such as the Shockwave. When shockwaving, a Gummination is dropped, but not on top of somebody but rather on the ground, resulting in a blast coming from a center point (the one gumminating).
That whining sound you hear when the celebrity, who very vocally supported Brexit, finds out that Brexit actually includes them and they have to get a visa to go tour...
When Iron Maiden frontman Bruce Dickinson found that ending 'freedom of movement' for EU citizens to the UK was reciprocated by countries within the EU ending his freedom of movement within the EU, he started gammoaning very loudly on Twitter.