These clips will stop your fitted sheet coming off the mattress. Slide the foot under the mattress, the long end under the sheet and the insert the button into the large hole from the outside of the sheet, pull the button up until in locks in place. See photos for example.

I use 4 holders one near each corner.

This will win you some serious points with your partner.

Creality

Ender 3

No

.2

25

Make the setting for the button as strong as possible. In testing my first versions of it the button would snap when locking in place. This version seems to be stronger and is holding up for me.