Are you growing that in orchid mix?

yes, gublers fine orchid mix from Lowe’s. switched all my hoyas to it and it is much more forgiving if I happen to over water.

How do you keep the plant from pulling out of it, or does it give the roots a firm foothold?

I only had problems with one pulling out, a trailing peperomia that was pretty heavy, in a small pot, and had a very tiny root system. Everything else has done fine, but I am mindful if it is a plant that trails over the side that it has a good enough root system to hold it in the mix or if the pot is a bit deeper that will help support it as well. my husband accidentally knocked one over and it made a huge mess and the plant went flying out of the container...so pros and cons...for me the pros outweigh the cons