Passive voice

It's a rather crude expression meaning that he is having ***. I don't see it as a passive construction. Being would make it passive, meaning that the person is not the dominant participant.

SO...Is the whole sentence present continuous tense?? What's the role of laid?

It's the same construction as in "he's getting angry", except that in "getting angry" you can replace "getting" for "becoming", whereas in "getting laid", as it's an informal expression, you can't.

If you dissect the sentence grammatically, it would mean to get "someone to lay on top of". (Female on top.) But in the present continuous tense, it doesn't mean the act is happening, but rather refers to a future possibility.

Yes, it is passive.
Contiuous tense. Passive voice.
Like: The building is getting built. The job is getting done.

Get laid means be laid; get angry means become angry; thus, they are not the same.

'Get laid' is a modern slang-based phrasal verb, and so 'get' is an auxiliary verb in the phrase...it doesn't have a particular 'meaning' on its own. Other phrasal verb examples: Make out, throw up..

'To get laid' is a slang term for having ***

the word "lay" has lots of meaning and one of the meanings is "to have *** with someone" but it's slang. For example:
Did you get laid? = Did you find someone to have *** with?

Wrong. It means "Did you have ***?"