When you and your girlfriend are performing anal, and she smears shit along your face, so you pull out and vomit directly into her gaping asshole.
Guy 1: Hey man, how was Tracy yesterday.
Guy 2: Things were going great, but then she got shit on her hand and made me chunderfunk.
Guy 1: Bro, I am so sorry.
The point at which you are so very, drunk/fucked that you Chunder, but not so very, very drunk that you are paralytic i.e. cannot talk. Therefore chunderfucked as opposed to actually fucked, totally trashed or absolutelywankered.
'Darling, I was so utterly Chunderfucked last night'