Someone or somethingthat sucks the most, out of a large group of things or people that also suck. This term was most likely created by Jose Cerquiera while playing Ultimate Frisbee, however it's true origins are not fully known.
A festival of sucking (oral sex) no one is quite sure how many or what type of people constitute a suckfest, the only sure thing we know is that it involves much confusion.
Oh man...I was f-ed up last night. I drank a handle of warm Mr. Boston gin and had a suckfest in the laundromat with a couple of homeless people.