Witnessing is the basic source. But it will be difficult to become a witness in the sex act if you are not trying to become a witness in other acts of your life. So try it the whole day, otherwise you will be in self-deception. If you cannot become a witness while walking on the road, don't try to deceive yourself, you cannot become a witness while making love. If just walking on the road, such a simple process, and you cannot become a witness — you become unconscious in it — how can you become a witness while making love? The process is so deep…you will fall unconscious.
You fall unconscious while walking on the road. Try it: even for a few seconds you will not be able to remember. Try it; walking on the road just try: I will remember I am walking, I am walking, I am walking. After a few seconds you have forgotten. Something else. has popped into the mind, you have followed some other direction, you have completely forgotten. And suddenly you remember: I have forgotten. So if such a small act like walking cannot be made conscious, it is going to be difficult to make love a conscious meditation.
So try with simple things, simple activities. While eating, try it. While walking, try it. While talking, listening, try it. Try from everywhere. Make it a constant hammering inside; let your whole body and mind know that you are making an effort to be alert.
Only then some day in love the witnessing will happen. And when it happens, ecstasy has happened to you — the first glimpse of the divine has descended upon you.