When lying in
bed with your spouse, you grab her/him tightly, wrap yourselves completely in the
blanket, and rip ass. It causes the fart in the air to become highly concentrated and, since you and your spouse are so close to each other, the temperature rises, further strengthening the fart. Meanwhile, your spouse is unable to
move, which forces her/him to smell it. You of course are immune to your own farts.