To understand the difference takes a little understanding of the Cabala. The first was one in unity Kether this is the supreme monad. But the God split the darkness and light.

This was the first split in the energy, it was the result of this split that gave way to motion. Here is the key motion Chokma then to Binah so there was a giving and receiving. Or pressure and a vacuum. This allows energy to flow, it also allows anything to move from one place to another actually.

It allows us to form the triangle of the trinity but I don't want to get ahead of myself, the Cabala can get complex.

Think of a pushing and pulling motion they work best when in full cooperation, that is why Aikido works so well.

This of fire and water, fire is violent expanding consuming. However water is calm contracting and does not consume but rather settles in.

Masculine energy is the force, the pushing, the expanding, the drive. Feminine energy is the acceptance, the pulling, the settling, and relaxation.

Masculine will burn something out of someone if necessary, feminine will remove pain and cool something down.

If you use Reiki it is regulated over by higher guidance of God and so can feel like your hands are like burning coals or like frozen ice blocks.

Because it regulates to what is needed, you trust it to work not try to decide yourself what may be needed.