I consider nosy a little more than what you’re asking, so you’re fine. :) I would not consider what Jill and I did grinding. In fact, I was hesitant, reluctant to even dance behind her for the possibility of it degenerating into sexual dancing. But she wanted me to dance behind her during the non-slow songs. There was nothing like grinding, however. I just held her and danced generally with her as she held my hands and I hers. Then on the slow songs, we slow danced. 

It is a sad phenomena that dancing and music has evolved or rather devolved into what it has, into sexual fits of mindlessness, sanity overpowered by potent throbs of music and movement. Thousands of years of the development of civilization, and what we do on a dance floor seems almost monkeyish. But morally done, it is a beautiful time, and indeed, it was. 

I am sorry you feel pressured to do that. But know that humans do not set your standard on any facet of life. Good times are assuredly had without grinding or even a hint of sexuality. If your date expects some grinding, set him straight (of course, he should be the spiritual leader) or find a new date. Sometimes, it might have to come to that. But most likely, the situation can be salvaged. 

Thanks for asking. :)