According to Tim Lane's article "Sex Before Marriage: How Far is Too Far,” what should be the fundamental starting point for decisions involving physical contact with someone when we are dating?
What Lane says is that the fundamental starting point for such decisions has to do with what is good for the spiritual development of the person that you are dating. Lane says that what you have to ask is
What does it look like to love and serve the other person in such a way that they are encouraged to grow in grace?
Practically speaking, what this means is that you should have very limited contact with a person that you are dating. This is because Lane emphasizes that you should not even have as much contact as might eventually lead to sexual desire.
Elsewhere in the article, Lane spells this out. He says that it is important to avoid practically all touching. This is important because he says that you should not allow yourself or the other person to get sexually stimulated. As Lane says
Touching that leads to undue stimulation that can only be satisfied by an orgasm or sexual intercourse should be avoided.
So, Lane gives both practical and spiritual advice. He says that you should do what is needed to allow the other person to grow spiritually. Practically speaking, this means no touching.