I have discovered this exercise with a Tantra Master around a decade ago.
I have waves of time where I do it daily. I’m in such a wave for the last months.
It’s very simple and powerful:
Laying down, relaxed, taking your both hands, each one to each one of your breast and letting them be there. They can simply rest, or you can also very gently massage your breasts, with the intention to relax.
This relaxes all the organs in your abdominal area, especially our feminine organs, because they are linked.
A great exercise you can add while or after (or before) is putting your feet together and allowing the legs to open wide, letting go of all tension in the hip area. For those with less flexibility, it can be done, one leg at a time - it’s also SO relaxing.
It’s also great to keep this area heated - I have come to realize along the years that some discomfort (also emotional) can come just by the fact that one part of our bodies is feeling cold, and with less energy. Two parts of the body that can influence us deeply are the kidneys and the breast.
Doing it for 20 minutes daily, is the not so easy part. In times when I am with a more optimized life, I find it more challenging to finding the time and space to be doing it - but I find that often those are the times when it’s the most needed! 
What inspired me to write this was to having the idea of doing it when I wake up in the night 
either in the middle of the night or when I wake up early, such as today.
As an extra inspiration, I share a book that might be of interest to you, where Young demonstrates that female power has always been inextricably linked with female sexuality.
Infinite Blessings.
