You weren't exactly sure how much coal the hot-tub needed to get hot with, but as you saw some steam coming out of the water, you took a dip with your finger to check the temperature, and it was that hot. Once it was filled, your girlfriend took the towel that she wrapped around her waist, and placed it on the edge of the hot-tub.
However. not only did your girlfriend decide to take off the towel that was wrapped around her waist, but also the one-piece swimsuit she was wearing as she was wanting to feel the hot water on the rest of her body. While you were stretching, and minding your own business, your girlfriend pulled your shorts, and underwear down revealing most of your privates to the people in the beach. You feel embarrassed, until your girlfriend places you in the hot-tub while you were distracted.