To freak out or to start freaking out. Usually when inebriated under a variety of substances. And then taking it too new horrible levals, most probally mentally scaring you friends and relitives with overwhelming weirdness, wigging in is where your soul itself feels as if it is imploding.
I was wigging in in that lift and started screaming it was fucking insane!
I was wigging in while talking to your mum last night she was speaking rubbish and i was off my tits