How to make a haramaki

Hi
I am pretty new to knitting and I’ve only ever made scalfs before. I saw these amazing tummy warmers from japan called Haramaki which are basically a snug-fitting tube which you wear around your waist/hips. Does anyone have any suggestions for how you could make one? It would need to be quite streachy and ideally knitted as a tube rather than sewn together at the end.
Thanks!

This would be really easy. You can try finding a bottom up sweater pattern that is knit in the round and just stop knitting when it gets to the length you want.

A variation on trvvn5’s approach. Meaure the widest part that the tummy warmer will cover. Multiple this measurement times your gauge. Multiple the number of stitches by 90% to get a snug fit.

Cast on the number of stitches.
Knit 2.2 ribbing, or ribbing pattern of your choice, for three inches.
Knit rows untill you reach the desired height
knit three inches of ribbing.
Use a streachy bind off. I like Jenny’s Surprisingly Stretchy Bind-Off.
You could add cables or other patterns to the body, just be carful how the pattern changes your gauge.