Okay, I'm honestly speechless. I've used one other "strapless" strap-ons before and have always needed a harness, because otherwise they don't stay put. The Midnight Rider wasn't going anywhere! I figured I'd end up using my harness, but neither my partner nor I ever needed it. Multiple positions and some aggressive f***ing and it barely budged! Not to mention the vibration on this is really great! Definitely intense, but so good and rumbly. My only complaint is that I wish it was about 1" longer. I tend to go for slightly longer toys for strap on use because I find it is easier to use in different positions. Otherwise, the size is nice and on the smaller end for folks who don't need a lot of girth.