Here is an image in which the area is marked in green: (NSFW, genitals covered). Please note how the 'string' of the taut adductor muscles separates the groin on the front side of the trunk from the area in question on the trunk's underside. The image shows a female body and the perineum is invisible below the genitalia in the shadow between the buttocks.

Context Explanation

(Image source -NSFW, explicit)