How do i shrink my jeans:)?

So I just got my baby phat jeans in the mail today, I been waiting for them to come and now that there here they fit to lose on my body & cause I been losing weight I guess I went down a size & I DONT want to return them back for a smaller size cause they took 4ever to get here so is there any way to shrink my jeans? Pls help me :(? Thnx