When, my nose has bleed I let it bleed because I hate taste of blood in mouth. Is it bad not to tilt your head back?

Quite the contrary. You should not tilt your head back, since you could choke on the blood. But you don't have to let it bleed, either. Pinch your nose, right at the middle of the bridge, and keep a firm grip for 10 minutes (watch a clock, it's longer than you think). The pressure will stop the bleeding. And be very gentle when blowing your nose and never pick it, since that's what causes most nosebleeds.
Tilt forward. Tilt your head forward, swallowing blood will make you vomit. Pinch the nose till the bleeding stops. Here is a video with more info for you http://www.Youtube.Com/watch?V=dp_i-gja7ui.