Whether your scene is bondage, breath control, or piss play, every serious pig needs to have a gas mask in his toy chest. Here is the grey version of the versatile Russian gas mask.
These incredibly sturdy Russian gas masks slide on quickly for a snug and secure fit. Put some duct tape over the eyes to kick things into high gear. You have complete control over what the bottom breaths. Blow cigar smoke up his snout or if you are really sadistic, cover the intake hole for no air at all.