[cupl4fun]

I do have some training in Koine (NT) Greek took 4 semesters worth in college. There just aren't any scriptures that can be seen as supporting swinging. Not without doing some mental gymnastics like "King David had multiple wives and concubines and God and His prophets never said anything about it. In fact God says through the prophet Nathan that he would've given David more wives if he had wanted them. Therefore God doesn't really care if people have lots of sex cause David did." But that's what this book would be.
Interestingly though all the scriptures which seem to be against swinging are gross mistranslations propagated by the Church. For example the word the church translates as "fornication" is the Greek word "porneia" which actually means "unlawful or immoral sex". Most likely meaning sex forbidden in Leviticus in this context meaning sex with animals, incest, temple prostitution, and rape to name most of them. But not meaning sex before marriage, and definitely not meaning consenting sex between adults.

I don't know any Hebrew though. Sorry Maple swingers.