What level of intimacy is generally acceptable for unmarried couples from the standpoint of the Bible?

Question

Possible Duplicate:
Sex outside of marriage is a sin. But what about "less than sex"?

Pre-marital sex is generally considered part of sexual immorality, ^[1] as such we should abstain from it as we do other sexually-immoral acts. ^[2]

But what does the Bible say about other levels of physical intimacy between unmarried partners?

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^{[1] 1 Corinthians 7:2}

^{[2] Acts 15:20, 1 Corinthians 5:1; 1 Corinthians 6:13, 1 Corinthians 18; 1 Corinthians 10:8; 2 Corinthians 12:21; Galatians 5:19; Ephesians 5:3; Colossians 3:5; 1 Thessalonians 4:3; Jude 7}