Boners are a natural reaction that’s pretty much out of our control so getting one and hiding it isn’t a bad thing.

It’s not okay nonconsensually involve someone in your stuff so making someone aware of your boner is absolutely not okay. Ditto for taking advantage of a situation like that to grope/fondle the person.

I’d need to know more to be sure (and to know specifically information you don’t know) but it doesn’t sound like you did anything to make anyone feel uncomfortable so I think there’s nothing wrong on that count.

It does sound like you’re extremely tightly wound sexually though, so there may be some stuff you should examine internally - like why that was so exciting for you. It sounds like you may need a more healthy sexual outlet if you’re reacting this strongly.