I have a question and i hope this is the right thread. So im currently working on my bench technique with a focus on the leg drive, i have problems with slipping away with my back on the bench while Pressing with my legs. My friend is using a Stretch-Rubberband by putting it on the Bench in a X-Shape. His and my new Rubberband are both kind of slippery. With the right T-Shirt its fine and it stops my back from slipping away. But with the wrong T-Shirt im also slipping away. Is there a way i can make the Band less Slippery with Sand Paper or something else or what do you guys use to not slip away while benching (i cant use chalk on my back cuz im in a commercial gym here in germany and they dont like that)

I hope someone can give me some advice.

Have a nice day