A mental gauge that every man has that is used to measure the presence breasts in any situation. It may also be used to measure the quality of breasts.
"Dude this party is bitchin'"
-What is your titometer reading at?
"After the busty volleyball team got here, I think it may have broken. So I'd say the titometer is reading just past titillating."
-I am on my way!
I liked that girl, but she barely affected the titometer.