This is one core aspect of sexual mastery.
For instance you might have a virtual chat with this potential lover.
The tone is light and flirty.
Suddenly one of you makes a more sexual comment and the magic drops.
Sexual energy between two persons is like a fine channel that grows organically.
You expose it to too much charge and it simply breaks.
It happens because either you or the other person can't take it.
When this happens live in love making, it creates disconnection.
You might be in soft foreplay and suddenly one shifts to more intensity.
That can be turn on or turn off.
It is like music.
You must listen to the mood.
Slow down!
Speed up!
Listen!
Be attentive!