It’s your party, so you can cry if you want to, but do it in the back bathroom, you’re bringing everybody down.
There are three proper times to use the bathroom while at tour birthday party: before, after, and during. Look, good GI health is more important than embarrassment. Unless, Johnny came to the party, he can’t know that you poop. Ever. Even when you two are married. You’ll have to wait until he leaves the house for the day and clean afterward. Oh Johnny, he can never know.
How many people did you invite? How many bathrooms do you have available? You may have to assign bathrooms to individual guests. I recommend a color coding system and charts.
Your mom worked real hard on that R2-D2 cake so if you have to “go” while the cake is being served, take some with you. As a sign of respect.
Did you invite Becky? You know she talks about you behind your back, right? Well, the bathroom is the perfect place to contemplate the perfect comeback to one of her jibes. Use your time while pooping multitasking and come back to the party ready for her worst.