When you step on the back of someone's shoe to make it come off, or make them trip.

When you eat dirt for the first time and leave your family to build a shack in the woods

A prank where you step on the back of somebody's shoe and make it fall off.

Variations:
1. Sandals. It is difficult to flat-tire a sandal, so a different strategy must be used. One way is to kick the sandal out. Occasionally, for fat, loose sandals, the normal method for flat-tiring works.
2. Boots. It is practically impossible to flat-tire an Ugg boot, so what you do is keep stepping on the shoe until it breaks, then they have to get new ones & you can flat-tire those.
3. Backpacks. When you flat-tire someone for quite a while, they become aware of you, but you've got another trick up your sleeve! Pretend to flat-tire that person, they'll dodge their shoe. At that time pull the back of their backpack & everything falls out.

1. a impotent man

2. a flaccid penis

3. a stupid or useless person

4. the prank of stepping on someone's shoe

when a girl tries to give a man a blowjob, but the man stays fully un-erect

the act of pulling your testical to the top of your sack, while holding in between your thumb and index finger the loose skin of your scrotum. Then pump your member and slowly release a testical of your choosing out into the loose skin giving the appearance of a tire being pumped up with air.
MUST HAVE A LOOSEY GOOSEY SCROTUM TO PERFORM THE FLAT TIRE. Otherwise injury and embarassment may occur.

a girl's boob that is smaller than the other one