Capricorns can be hot and then cold in seconds. One way to turn a Goat off so quickly it will make both your heads spin is to critique them while you're messing around.
Whether you're pointing out what they're not doing quite right or bluntly telling them to try something else, a Capricorn will interpret that as rejection.
Fortunately, Capricorn values deeds and will make a great effort to express their affections through them.
So, positively suggest something "I'd love it if you..." "That feels amazing, I wonder how it would feel if you..." or guide them by taking charge. Capricorns like to be dominated in bed!