(n) (1) A same general vicinity or idea as something else; an estimate of the scope and range of something.
(vb) (2) To estimate or approximate.

The area between a female's pussy and asshole; where your "balls" are "parked" while fucking girl missionary in the pussy, or doggy-style in the ass.

When there is a hobo sitting on the end cap of the parking lot, you are so fascinated by how poor he is you forget to put on the brakes and your front wheel ruins his testicles.

v. 1) estimate. A word, based on an obscure reference, that makes no sense to non-Americans.

2) a sexual practice.

A sex act performed during ejaculation. The guy is doing the girl "doggy-style" and when he starts to cum, he pulls out, rests his dick between the two cheeks of the girl's ass and cums onto her back or asshole. The term "ballpark" is used because the dick between the buttcheeks resembles a Ballpark hot dog in a bun.. One game guys can play with this is to see how far he can cum on her back.. make a note, compare with friends.

To sneak up behind someone, grab them by the hair, pull their head back and then reach around and smack them in the face with a raw hot dog.

A "ballpark" is when a female uses her ass cheeks to jack a guy off. It is referred to as ballpark because of its visual similarities to a ballpark frank hot dog held firmly with in its bun.

In laymans terms: ass tug.