Not DIY but, it's cheap and easy.

Unlike my ex this cheap and easy product is actually super useful and worth the money you spend on it. It is called Tenacious Tape made by Gear Aid. Its listed as a tent repair tape but, can really be used to fix just about anything made from synthetic fabrics, tents, raincoats, waders. etc. Best part is its waterproof! It comes in an easy to use and carry tube about the size of 2 C batteries end to end. I carry one in my sling pack all the time. This stuff isn't a quick duct tape style fix either it can really be used as a permanent fix.

I ripped my waders last October when I slipped on some volcanic rock and ripped a quarter sized hole in the butt of my waders. I took them off cleaned the dirt off the best I could and with my knife cut a square of the Tenacious Tape a bit bigger then the hole. I then made sure to press very hard all around the repair to really seat the glue into the fabric. Within 10 minutes I had a water proof permanent fix to my waders. The repair is still holding strong almost 6 months later. For 5$ this very versatile tape can't be beat. I have had this roll for about 4 years and it hasn't lost any strength and I still haven't used it all up.