The best things in life are sweaty, no one has ever proven me wrong.
As luck would have it, some of the best, sweaty things also happen to be what we were put on this planet to do; survive and reproduce.
Everything it took to get us humans to get where we are today, like traversing terrain by running, climbing, crawling, swimming, and jumping, were necessary to find and chase down food, or not to become food ourselves. We needed it to survive. Now that we aren't in a constant state of survival, these things have become (and always truly were) incredibly entertaining ways to sweat, move, play, bond with others, and improve our overall health.
Fighting and hunting are lumped right in there. We may have needed to band together with others in order to take down prey or defend against potential predators/enemies as a way of life before, but combative arts and weapon play can now also serve as wildly fun ways to get sweaty, healthy and bond with others as well. There's nothing like a good sparring session to really make one feel alive and happy as hell...
Except, maybe, reproduction.
Now THAT is a way of moving, playing, sweating, and bonding that most everyone can agree is, by far, the most enjoyable and entertaining. (#GetSweaxy. It will be a thing!)
Regardless of which category is the most fun, survival and reproductive movements also have something very important in common-the more effective your hips are, the better you can potentially perform.
How to bang like a boss
The phrase "put your back into it" has been used an unbelievable amount of times and totally holds true in some regards. During sex, however, isn't one of those times.
A top notch sexual experience is going to require one or more of the parties involved to be able to flex and extend their hips in powerful and repetitious ways, while getting the glutes, hips, and legs to provide most of the support/power to be the safest and most effective.
There's too much sheer force on the lower back when the rump doesn't do it's part.
So, I guess one could truly say "hump with your legs, not with your back."
Getting control of your ass.
The following routine has been made with the intent of getting "in touch with one's hips" by exploring/developing awareness of pelvic stability and mobility whilst in a few various positions one may find themselves in during a nice hearty... session. So please proceed as you normally would and really pay attention to not only what you're doing, but how you're doing it. Be as stable and engaged as you can to maintain relative structural position and only move where you want to move for any given drill.
As per usual, only move into a place of discomfort while keeping the best form possible throughout, and never go into pain. The more one can clearly define and ride the line between discomfort and pain, the more one can safely and effectively accomplish the task at hand.
Once the rounds and reps go along a bit, and positional awareness develops, feel free to challenge yourself as you see fit, possibly by picking up the pace a bit
Granted, there are plenty of other components to sex, like various emotional, psychological, and "self control" aspects that can mainly only be addressed at the time of, but being more sure of the required movements beforehand can help bring some much welcomed confidence to the table, or bed. It's much easier to gain control of the intangible once we get control over something tangible.
Most importantly, just having fun is totally key. So, do that.