is reached just before orgasm.

In the woman, the clitoris is drawn forward and retracts under the clitoral prepuce; the lower part of the vagina becomes extremely congested (formation of the orgasmic platform), and there is increased nipple elevation.  

In men, the vasocongestion leads to distention of the penis. Heart rate increases to 100 to 175 beats per minute and respiratory rate to approximately 40 respirations per minute.