the best one i ever heard was when i was in the British army and it was called the
Tampax Factory and it goes a little some thing like this

You can tell by the smell that she isnae very well
when the end of the month comes around
You can tell by the taste that it isnt salmon paste
When the end of the month comes around

Singing aye aye ae tampax factory
sing out your orders loud and clear
we have large we have small we have familey size and all
when the end of the month comes around

you can tell by her moaning that she's passing haemaglobin
when the end of the month comes around
you can tell by the stench thats eminating fae her trench
when the end of the month comes around

repeat chorus

and so it goes on very crude but very very funny when your on a rugby tour in the army and all the lads are being lads
Cheers for the thread
Dylan