-Warm Apple-Prune juice - Gerber makes a small 4oz bottle sold in most grocery stores, so you don't have to buy a giant thing of prune juice. I know warm juice just sounds nasty but it seems to have helped. A tip: Don't overdue the prune juice or you'll have a baby with a tummy-ache and poop everywhere!
-When he cries hold him to your chest upright (gravity can only help at this point) or lay him on his back and rub his tummy counter-clockwise. Trust me the screams and pushes are really sad but there is not too too much you can do.
-Keep your baby in loose clothing - jeans and tight waisted pants are a bad idea. A onesie or romper work best. Also give your baby room to wiggle. Lay a blanket on the floor for tummy rubbing for example.
-If you know what is causing the block, STOP feeding it to your baby. In my case it was a new kind of formula, I immediately went out and got the old kind.
-If the problem doesn't seem to go away in 12hrs or there is something that should not be in the diaper when the time finally comes, it's time to call the pediatrician and they may tell you to use a laxative. But don't use one without your pediatrician's recommendation (Children's Laxatives are recommended for children 2+)
I hope none of you have to experience this, but if you do, I hope this helps!