it won't stop bleeding
 

I was going around the car bleeding brakes, and all was good until i got to the rear passanger inside nipple. I had my brother pump the brakes as usual but when i cracked it open, i couldn't close it. I tried to tighten it lightly like all the other ones but it is still slightly open. Now even though it's close, if i push the pedal down fluid still comes spewing out. And even with the pedal not being pressed down fluid is still coming out of this nipple slowly. What is going on here? Help please asap i dont' want to wake up in the middle of the night noticing that my whole brake master cylinder is empty because of this damn nipple that won't close.

You could try to unscrew it all the way and take the nipple thing all the way out. Make sure nothing broke off the nipple piece or fail inside. Check the threads and make sure they ain't wore out. You could take out the other side of the calipers nipple and see if they are the same size to check the braking issue. Thats just a theory from me looking at my calipers I have sitting around, I could be wrong.

Bleeder valve might have dirty threads and cannot be closed properly or it was previously overtightened and cross threaded

if i remove the nipple would the brake fluid start spewing out. since it's now just trickling out slowly with no pressure on the brakes.

Yes, it will gravity feed out. (Don't get that stuff on the paint, btw.)

Get some small pointed rubber stoppers at your favorite hardware store and pull the screw out, then plug the hole with a stopped.