To understand how a sub really works you will need:
one plastic bottle, one rubber pipe, a basin/tube, sth sharp, water, a marker
1.name your sub by writing her name on the bottle.
2.make three holes in the bottle. (make sure one of them is a bit smaller than the tip of the pipe.
3.put the pipe into one of the holes.
4.pour water into the basin/tube
5.put the bottle horizontally, push it downwards so that water gets into the bottle.
6.put the other end of the pipe in your mouth.
7.blow (no, not your girlfriend/wife, blow into the pipe, dumbass) to surface.
8.profit?
click "I like it" if you liked it.
Edited: bcoz i'm a dumbass myself. thx donna