Try searching バーチャルYouTuber 同人 マンコ on DLsite (R18). If that fails, the doujin may have been deleted or the title misremembered beyond recovery. If you can provide any additional context — such as the platform where you saw this string (Twitter, 4chan, a forum), the approximate year, or any character names — I can help narrow down the search further.
But "Iribitarigal" doesn’t match any known series. Could be "Iribitaru Gal" (イリビタルギャル) — which might be a misspelling of "Irregular Gal" or "Virtual Gal" (バーチャルギャル → "bācharu garu" → mis-typed as ribitaru). doujindesutviribitarigalnimankotsukawas upd
So the intended phrase might be: ("It's a doujin: Virtual gal using p***y on two men – updated") the approximate year