Unsecure joining knots due to nylon yarn used

I am making a skirt out of very stretchy 100% nylon ribbon yarn. I noticed that every time I try it on for size the knots for joining a new ball of yarn are not staying secure. Is there a special way to treat joins for nylon so they won’t slip out?

I saw this on DIY Knitty Gritty the woman sewed the two ends with matching thread so that there was no knot. I am also using a ribbon yarn and that is what I am doing and I can’t find the joins on it.
Maybe someone else has a different way of doing it, but this works for me.
Just make sure that the thread is matching color of the ribbon yarn.

I very rarely knot yarns. I just weave them in.

Because these ends are slippery little beggars you could tack them d own with matching yarn when you’re done with the project. I wouldn’t do it before because if you had to frog it would be a nightmare.

Thanks to you both! I chose not to knit with both strands together at joins because I didn’t want excess bulk to show on this smooth shiny yarn so I settled for a knot. I will follow your advice and untie, weave in, and sew with thread!
lml :muah: