The Sacred Mountain is on the north of the island. From Sacred Mountain you can walk southeast to the Waterfall.
At the moment there are two places you can visit at the Sacred Mountain: the Sexual Wisdom Temple and the Cave.
Sexual Wisdom Temple
The Sexual Wisdom Temple is located at the top of the Sacred Mountain and is the location where you can learn new sex positions.
You can purchase the following new sex positions in exchange for EXP points. You can purchase different positions whether you're a man or a woman. Most of those positions are for premium players.
The cave is a hidden location. To get there you have to click the branch of the tree on the left side at the bottom of Sacred Mountain to reveal a lever. Pulling the lever opens the door to the cave.