In JAV (and related adult content),
"喉ボコ" (nodo boko) or simply
"ボコ" (boko) is the standard slang term for the visible
throat bulge that happens during deep irrumatio (throat-fucking). It's extremely common in titles, tags, and fan discussions.
Why "ボコ" (concave/hollow) instead of "デコ" (convex/protruding)?
Your confusion is totally understandable—logically, a bulge is a
convex protrusion (凸 = deko), so you'd expect "喉デコ" or something with 凸. But Japanese slang here doesn't follow strict kanji logic for shape. Instead, it comes from how the bulge is
perceived and described in the scene:
- From the outside (the viewer's/camera angle), yes, the throat visibly bulges outward (convex).
- But the term "ボコ" draws from 凹 (boko/boko), which means concave, dented, hollow, or a depression/pit. The idea is that the penis is pushing in so deeply and forcefully that it creates a visible "dent" or "hollow" effect on the neck from the inside — like it's caving the throat wall inward (even though the skin stretches outward).
It's more about the
action and the
forceful intrusion than pure geometry. The cock is "boko-ing" (poking/hollowing out) the throat, and the resulting lump is the evidence of that. Japanese onomatopoeia and slang often prioritize the
sensation or motion over literal shape.
This is similar to how "deko boko" (デコボコ) as a compound means "bumpy/uneven/lumpy surface" (mix of convex + concave), but in this specific fetish context, the community settled on
"boko" alone for the throat effect. It's not a formal dictionary term—it's pure JAV/fetish slang that evolved in forums, tags, and video descriptions.
It's one of those quirks where the slang stuck because it
sounds punchy and matches the aggressive "poking/hollowing" vibe of the act, even if the visual is technically a protrusion. If it were "deko," it might feel too neutral or head-related (like "deko" for forehead bump).
So yeah, you're right on the kanji meanings, but JAV slang took the "intrusion creating a hollow" route instead. Classic case of fetish terminology going its own way!