How to make players slide when they walk on rough terrain? [Like in booga booga]

I know this isn't a request site, but there aren't other sites to post this question. Also, I'm not requesting for a script.

I want to make players slide when they walk on rough surfaces, just like in booga booga. I changed the terrain's friction in custom physical properties to 0.004 and the friction weight to 100, but it just makes the player slide on normal surfaces.

Thanks if you took the time to look at my post.