I have heard others say they got their sims to woohoo in the dressing room. I have a romance sim who wants a public woohoo. But, when she is on a date with someone it wont even give me any options when I click a dressing room. How do I do this?

You have to have one of them getting changed in the change room, and get the other one to click on the change room and there should be an option.

If it doesn't come up, their relationship probably isn't high enough.

Choose the sim you want, click on the clothes, and order him to try on a dress of any kind.
When the chosen sim is in the booth, still chosen, click on his date (don't make it playable), and search for the option "join to"...woohoo. The date will enter the booth.

Thanks you guys, I am off to try this!

I think the option is listed as "ask to join".

The procedure is also very similar for woohoo in a photobooth.

I think I got this option once, then it just disappeared. Doesn't matter who it is or how high the relationship.
I need to try it out again.

You need to be quick on the button. Ask as soon as the curtain closes. (It also helps if you pause while you are giving the order.)

I was hoping someone would have any insight about dealing with the glitch that comes with this but all I'm finding is threads like this one. My Sims have full relationship bars and I'm pausing the moment the curtain closes and have tried multiple times but half the time the woohoo option doesn't even show up and when it does, the sim getting changed has already left by the time the other tries to enter, and I start them out standing as close as possible. Someone please help

Hey @AccursedThing

Which version of the game are you using- UC, disc install or Legacy? Are you using mods/ custom content? If so try this guide- remember to backup before doing anything!
Game Help:Game Problem^wiki

If this doesn't help, then start a new thread in the game help forum:
https://modthesims.info/f/31/
Give info about your game setup and mods, and people will help you.