It sounds like you’re over tightening the strap. Positioning is crucial. Always tighten the strap when at the lowest position after plugging it in and it recalibrates. If the strap is clearing the head and the strap is overtightened, well it’s like trying to fit into a hex nut the size of a dime. You may need to lower the stroke range at first then increase.

It’s easy to think tighter strap = more sensation. But it has the opposite effect since it deforms the sleeve to the point where all the grooves smooths out on the interior walls.

Although it says it works without lube, I’d argue you’d be doing yourself a disservice. 100x better with lube.