[IcanseetheLight]

I have given a variation of this as a punishment before which has the advantage that it doesn't need days of preparation.
All you need is a bunch of cotton balls and a hospital breathing mask (or maybe one of the breathing masks for DIY, they have a more rigid shape).
Take the cotton balls and stuff some of them inside your underpants, make sure some ride up right into your buttcrack. Put some more cotton balls under your arms and fix them there with tape or ace bandages.
Then go to the gym and work out for an hour or take a good long jog. Make sure you work up a good sweat.
Now all you need to do is take out the cotton balls, put them inside the breathing mask and you're done. Wear the mask while doing cornertime or during (self-)bondage.
Obviously make sure you can still breathe.