RenegadeWater said: what the.....fuck? can someone please explain?
She's being milked while the tentapipes are either putting something in her or regulating something out. Possibly both. It's a fairly common set-up in the "girls captured in science labs" fetish. Maybe something is growing in her big belly that has to be sustained on certain types of alien nutrients that the human body doesn't produce on its own.
The explanation for this is dependent on the context of the artist or the hentai game it's from, but it usually boils down to lolscience.