your back is very easy. Before you go to bed tonight, go into your garage and find the duck tape.  Have your wife apply vertical strips from your lower back to your shoulders until all the hair is covered.  Then go to sleep, on your back.  When you get up in the morning, just have her rip off the tape and you should be pretty much hairless.

If you are wanting to do the bikini line I'd leave that to the professionals.

Be sure to report back on your results.