How do I ask my mom to be in her best behavior without hurting her feelings?

JUST BE HONEST WITH HER AND TELL HER THE WAY YOU DID HERE.[EXAMPLE] MOM WE NEED TO TALK ABOUT SEATING ARRANGEMENTS AT THE RECEPTION. HIS PARENTS ARE A LITTLE DIFFERENT THAN WE ARE AND I DON'T WANT YOU TO SAY ANYTHING OUT OF THE ORDINARY AND POTENTIALLY EMBARR ME.PLEASE MOM THIS IS A VERY SPECIAL DAY FOR ME & I EXPECT YOU TO RESPECT MY FEELINGS ON THIS. OKAY? SAY I LOVE YOU MOM HUG HER AND HOPEFULLY EVERYTHING WILL BE BEAUTIFUL GOOD LUCK & GOD BLESS