I heard Army boys do that all the time during offfield. When
they need to s-hit, they'll dig a hole in the ground b4 doing their
business.
Have u guys (or gals ) ever done that b4?
I've done them twice(bo pian, no toilet in sight..si bei urgent )
during my cycling trips.
1) Tampines BMX park (can;t get to Tamp mall in time and even if i
do, who look after my bike? )
2) Pulau Ubin (eh, in the middle of a thick forest how to find
toilet? )
my friend went 1 step further...on the way up to Mt.
Faber!!!!!
we were riding up faber hill when he suddenly says he needs to
answer nature's call.
So I helped him keep a lookout while he peed into the drain along
the road.
Lucky no cars passed by!
However, I make it a habit to mumble "excuse me, excuse me "
whenever I'm peeing at somewhere other den into a toilet
bowl/urinal.
Mum says its to warn sleeping spirits b4 u unlease a waterfall.
any of u have experiences to share? 
