1. Unzipping tight pants after a huge meal.
    Or when you really have to pee.
  2. Having someone massage your head or shampoo your hair for you.
    At the salon and at home (bow-chicka-bow-wow)
  3. Jumping into freezing water.
  4. Having your back scratched/rubbed as you drift off to sleep.
  5. Taking off your shoes at the end of a big day
    Suggested by @solena
  6. The moment you step into air conditioning after being in the summer heat.
    Suggested by @roche
  7. Sinking into a hot bath after a stressful (or freezing) day.
    Muscle relaxing bath salts, too, please!