(noun) Large breasts.
Also: "Tig Ol' Bitties" (American Southern pronunciation)

switch the t and b around and you'll have big titties. This phrase is used to express the size of a woman's breast when you cannot contain yourself in her presence and feel the urge to verbalize your discovery.

When your walking in a public place with your friends and you see a girl with nice full bodacious breasts. You wanna say something to your friends without alerting the big boobed girl, so you say "Damnnn looked at them tig bitties"

What you call a girl with titties that are supersized.

really means big titters, which means someone has nice breasts. Usually used by dudes in discreet way to talk about titties while in a social situation or in the classroom with out anyone being the wiser.

large, voluptous, watermelon-sized breasts