If your goal is to let down your inhibitions, then you should be prepared to say yes in many of those situations you described. Of course, you have to stay safe - that's where those inhibitions come from in the first place. So decide ahead of time what your limits are. Then, if the situation doesn't violate those limits, go for it.
For example, it seems to me that, if someone asks you to dance, unless they are totally creepy, you'd want to say yes. It's just dancing, and dancing is fun. If the dancer then asks you to go home with him, that might be the time to say no. A guy invites you to a coffee shop for a snack, yes. He asks you to get into his car, no.
Pre-planning your boundaries will free you to have some fun. Some of that pre-planning can be specific safety plans. Of course, carry your phone with you. Share your plans, and arrange check-in calls: "If you haven't heard from me by xx:xx, start to worry."
The solution for events that you are not mentally prepared for is to prepare yourself mentally.
Get out there and have fun!