Thin nylon tights get pulled over a guy’s legs and hips, giving everything a glossy, smooth look while still showing off muscle definition and a fat bulge underneath. A lot of scenes lean into teasing foreplay like rubbing through the fabric, tugging the waistband down for a blowjob, or ripping a run in the material right before fucking. The contrast between delicate hosiery and rough male-on-male sex is usually the whole vibe.