Sneezing and farting at the same time. Fart is usually caused by the sneeze.

*For men- it can also mean starting to urinate and farting simultaneously. R to the D.
Yo, did you just sneeze and fart? That's a bothender! **To bothend
by oL Skool Ru November 27, 2014
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When your stomach is so messed up you have diarrhea and are throwing up at the same time, hence you are expelling nasty material out of both ends
Man, I ate that undercooked Mexican food last night, and I've been in the bathroom with bothends since then.
by Redinamus September 9, 2017
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