Edgy-but-safe textures

Use materials that have a slight “bite” or kinky feel without real harm. E.g., leather or latex garments can be dragged across the skin (they have a distinct sensual drag and smell), a length of rope (unraveled rope ends brushed lightly can prickle pleasantly), fishnet or mesh fabric pressed on skin leaves patterned impressions, even skin-safe adhesive tape (like bondage tape) lightly placed then removed for a tingly sensation. These introduce a hint of roughness or friction that some find thrilling, without significant pain.