The act of inhaling methane out of one's anus. This is commonly performed during foreplay, but is also a quicker, less potent alternative to the huffing of manufactured jancum.
1. My wife likes to be butt-huffed.
2. I need a quick fix. Drop your pants and let me butt-huff you.
3. That girl's really into butt-huffing. I'm gonna go eat some chili...