Great news; you can. There's a simple technique in neuro-linguistic programming (NLP) called anchoring, and you can use it to recapture a positive feeling whenever you'd like. But to do that, first you have to get the positive feeling in the first place.
Many people can think themselves there. Think of someone you love dearly; a friend, a family member, a partner, a child, or even a pet. Think about them and start to feel them deeply. Allow the glow of that good feeling to spread throughout you. Alternatively, think of your happy place, a beautiful memory, or your happy song. Use whatever you can to get yourself to that place. For me, any of the previous techniques work, or I can also do this after I've meditated or engaged in any physical activity that gets my endorphins flowing.
Once you have that positive feeling, come up with a unique gesture while you still inhabit the sensation. Make it a unique (to you) gesture; not one you perform daily. It could be tugging on your right ear with your thumb and forefinger, or making an "OK" sign with your left hand, for instance. Make it a specific gesture. And, while you are still in the feeling, make the gesture several times. As you repeat the gesture, do it exactly the same way each time. Do this until the intensity of the positive feeling begins to subside, and then stop. Alternatively, make the gesture and continue to hold it in position until the intensity of the feelings begin to lessen.
Now, any time you wish to return to that place of positive feeling, repeat the gesture exactly as you did it. That's it. It's effective and easy to do.
For energy healing practitioners, this is a great technique to teach your healing partners. At the end of their session when they're in that relaxed and positive state, teach them the technique and tell them they can return to that feeling anytime they wish by repeating the gesture. Allow them to choose a gesture that is specific and meaningful to them.
One word of caution to practitioners: Sometimes a session stirs up old, stuck negative energy, and your healing partner may be processing old negative emotions at the end of and after a session. When I observe this happening, I try to continue with additional energy until it passes or initiate a visualization to help them feel safe and peaceful, but sometimes it may take a few days for all of the emotions to process. If you observe this is the case at the close of a session, don't teach anchoring because that is not a feeling your healing partner wants to return to. Instead, wait until a laster session when your healing partner is in a positive and relaxed state.