RIDDLE OF THE WEEK

We worked together in the dark,  we didn't need to see each other, though having light would have made our meeting easier.
Our kisses were not precise, we let them fall wherever they may,  knowing that whichever place it fell didn't matter as long as the pestle entered the round hole, satisfaction would most likely be guaranteed.
Though of course, satisfaction would come faster with expertise and experience.
Whenever we touched each other , we made different sounds,  depending on the pressure and how hard we met. Either way,  as long as there was a meeting, there was a smoothening .
We had been pounding for a long time now, grinding continuously, our tempo increased because we were close, about to reach our desired ...............


Complete the narrative with one word and who/what are those working together here?

First to get the answers correctly, wins an awesome price.