What is Thaas It!?
1.
a Masuadism; the exaggerated form of 'That's it!'; alternate spellings include thaass it!, thasssss it!, and thaaaas it!; The more you want to emphasize using this phrase, the more a's and s's you add on to it.
"You're retarded." "Thaas it!"
"We should go get some Cotijas." "Thaasssss it!"
