This is an essential part of your tantric experience.
The build up of sexual energy will often be associated with a fertile sexual imagination.
Your sexual energy simply feeds your mind and activates your fantasy world.
It is normal.
You might see yourself having sex with other women or men.
You might have visions or desires you did not have before.
All this is healthy and normal.
Most of these fantasies are not meant to be manifested.
They are simply the mind reflection of your sexual awakening.
In the beginning, some of these images can almost be shocking because you envision scenes you can feel ashamed of.
No worries again.
All this is normal and is a simple “clarification” of your mind.
Enjoy these visions and fantasies.
Don’t focus too much on them as if it was something meant to happen.
Simply observe them as if you were watching a movie on a screen.
Every now and then, see if you can influence these fantasies.
Remove those you don’t like and stimulate those which do thrill and excite you.