How to squeeze during sex?

I have been practicing at pompoir for awhile (started this winter, been on and off due to my busy schedule), usually I do pelvic floor exercises, yoga and wearkegel balls. I have been successful at figuring out how to squeeze while using fingers, and actually accidentally ended up squirting recently while doing this, which is kind of a win, I guess. However, I've noticed that when I'm actually having sex with someone, namely during PIV, I cannot really do much with my pelvic floor. I try to, but the movement makes it hard for me to focus on engaging it and makes my pelvic floor feel quite weak. Do I just need to keep at the exercises? What can I do to make sure I'm engaging these muscles when if actually comes time to do the deed?