My eldest thinks I am a humgruffin- whatever it is I have no idea, but I really like the idea of being one.

He thinks he is a gigglemug

Not so sure but he is a tit

Our 4 yr olds best insult was always ‘you big fat belly rat’

Snotgobbler. My daughters’ name for one of her brothers.
Slobspawn - speaks for itself, really.
Anticipointment - When a looked-forward-to event fails to live up to expectation.

One of my favourites is intertwingled, a portmanteau of intertwined and intermingled.

Sounds like someone is being a gigglemug themselves.