Every level of sexual experience is so immediately gratifying that it’s nearly impossible to be satisfied by previous levels.

These desires are a fundamental part of everyone’s biological and psychological makeup.
In fact, if you don’t feel your partner’s strong physical desire to be close to you, a crucial element may be missing.
When all of these work together and rise, add the icing (physical intimacy).
A cake, like a romantic relationship, is incomplete without icing (at least some physical sign that this person is more than a friend).
When it comes to intimacy, the million-dollar question is "How far is too far?