Depth of trance
How deeply someone is hypnotised is often an indicator for how successfully they'll be able to actively engage in some of the sexual activities discussed on this site and in Look Into My Eyes. Someone who is only very lightly hypnotised may, for example, still benefit from the relaxation and openness associated with the trance, but may not be able to contribute to their partner's enjoyment any more than a wet fish could, i.e., they may only be able to silently lie there.
Working out how deeply hypnotised someone is becomes easier with practice, of course, but there are a few things you can look at which will give you a quick indication.
Facial expression and body tone
As you hypnotise your partner, you should see them physically relax and their breathing should become slower and shallower. Once you think they're hypnotised, one of the first tests you can do is to check how physically relaxed they really are. You can do this by lifting one arm by the wrist (figure 1). Lack of resistance and tension are good signs..
Next, instruct them to lift their head and open their eyes (see figure 2). Their face should remain relaxed and their eyes staring vacantly ahead.
How well they physically respond
Someone who is only lightly hypnotised can seem lethargic may have difficulty following your instructions, such as if you tell them to sit up or to answer simple questions you ask them. The general impression you can get is that they're feeling heavy or lacking in energy. When they speak it can seem quite slurred or even unintelligible.
As they go deeper into the trance, this lethargy can go away. When you tell them to sit or ask them questions, they will respond easily. It may even seem difficult to believe that they are actually hypnotised, but when you tell them to relax, they'll relax totally, usually more than they can when they're awake.
Simple post-hypnotic suggestions are also good tests. If you give your partner a suggestion that, say, five minutes after you wake them from the trance that they will drink a glass of water, you will be able to see how responsive they are.
Someone who is hypnotised, or who is responding to a post-hypnotic suggestion, will do so quite literally without any embellishments. For example, if you tell them to stand up and take a few steps, then when they're hypnotised they'll likely do so with their eyes closed because you didn't tell them otherwise. Someone who isn't hypnotised would more than likely open their eyes when following these instructions.
It follows that when someone is deeply hypnotised, they're not going to respond sexually until you actually tell them to. This means that if you only instruct them to get into a sexual position or pose, they'll normally be sexually unresponsive. We can see this in figure 3. Although the woman is in what could be called a sexually receptive or exposed pose, there are no signs of lubrication or glistening around her cunt and her facial expression is blank. She would need further commands to become aroused.
If you're particularly keen on testing and understanding the depth of trance of someone, hypnosis researchers have developed more objective tests and scales. The Stanford Hypnotic Susceptibility Scale is one such.