arrive to a party- is it possible to use the preposition to?

Proposition yes, but not "to". You'll arrive at a party.

No. In American usage at least, one would say "arrive at a party." You can go to a party, but when you get there, you have arrived at the party.

I guess I was ahead of myself. You can get propositioned at a party
but actually I meant to say preposition.

I didn't notice that at first . . . damn, i missed a wonderful opportunity to have some fun at your expense . . .

You'll find other opportunities to do that

While we're on the topic of sex: in French, "j'arrive" is sometimes used in place of "je viens" (I'm coming or I'm about to come).

I would write:

What do you do when you arrive at a party?

Yes, but neither "j'arrive" nor "je viens" mean "I am having an orgasm". The verb for that is jouir. So it would be je jouis.

Using the verb "to come" to mean "have an orgasm" is idiomatic English, and idioms don't usually translate word-for-word. Incidentally, how I hate that awful word "cum". God only knows where it originated.

"cum" is latin for "with" - like magna cum laude, but how it arrived at
the orgasm scene, I don't know either.

Incidentially, in German we use the same term as in English:
"Ich komme" (I come) referring to having an orgasm. Probably originated
from the German language anyways....

Their literal definitions have nothing to do with orgasms, certainly, but they are slang terms for having an orgasm. They appear on French TV all the time.