This should really be titled "gratuitously sexed TV shows". Oversexed would be more like the show is young, horny and always looking for sex.
  1. Rome
  2. The Tudors
  3. True blood
  4. Entourage
  5. Sex and the city
  6. Melrose place
  7. The Borgias
  8. Game of Thrones
  9. Californication
    Suggested by @videodrew