The goth subculture is a contemporary subculture found in many countries. Its imagery and style indicate influences from nineteenth century Gothic literature along with horror movies and to a lesser extent the BDSM culture.
The goth subculture has associated tastes in music, aesthetics, and fashion, whether or not all individuals who share those tastes are in fact members of the goth subculture. Gothic music encompasses a number of different styles. Common to all is a tendency towards a lugubrious, mystical sound and outlook. Styles of dress within the subculture range from deathrock, punk, androgynous, Victorian, some Renaissance and Medieval style attire, or combinations of the above, most often with black attire, makeup and hair. (more from Wikipedia)
Howard and Raj dressed up in Goth clothes and wore "tat sleeves" to try to pick up girls at a Goth club in Hollywood. They more or less hit it off with Bethany and Sarah, but when the girls took them to a tattoo parlour, everything fell apart.