@girlsoconfusin - Doing it with a therapist is always the best approach if you are able to, but if not then you can still learn about it and get the general idea. The YouTube channel "OCD and Anxiety" has a lot of good information on it, in bite-sized videos that cater to many different themes. I'm sure he has some on sexual orientation triggers.
The key with practicing ERP is to take things slowly and to find exposures that are just outside of your comfort zone. You want to work your way up to the more intense exposures at your own pace.
As for the fear of blurting out inappropriate things, that's just another intrusive thought. One of the most common responses taught by OCD specialists is, "maybe, maybe not." When you have the thought, "I'm going to reveal something inappropriate about myself," try to respond with, "maybe I will, maybe I won't," and then focus your attention on something other than your thoughts. Or if you get intrusive, "what if..." thoughts, try responding with, "so what?"
The point is not to argue with the thoughts or try to disprove them. I promise you that constantly focusing on those thoughts does nothing to increase or decrease your chances of acting on them, and neither does NOT focusing on them. That's because ultimately, thoughts themselves don't "make" us do anything. But if you give those thoughts a lot of attention because they make you anxious, you'll condition the mind to look out for those thoughts more intently, and thus they will arise much more often.
The fact of the matter is that these thoughts will probably arise while you're on this road trip. But that's totally fine! Those thoughts can be there and you can still have a good time. It's just a matter of not getting wrapped up in them.
Think of it this way: if you go on the road trip and have a good time despite your fear of these thoughts, you will be training the mind to be less afraid of them. It's actually a fantastic opportunity for you. Try to view it as more of an experiment; a chance to see how your body reacts to being in a situation that you are mentally afraid of.
Try having the attitude of, "I'm going to go on a roadtrip, AND I'll probably experience intrusive thoughts that may or may not stress me out." As well as, "maybe I'll say something I regret, and maybe I won't."
Always always always bring yourself into the present moment. If you start to feel stressed from intrusive thoughts on the trip, take the time to notice how you physically feel the stress. Just be aware of it without fighting it. All of this is about non-resistance.