The novel's protagonist practises the Taoist method of sex. I've never heard of this method and Pei Ee dismisses it as utter rubbish. The whole point of it seems to be achieving longevity through not losing your ching. Here's a quote for everyone's amusement:
To achieve one thousand loving thrusts was within any man's capacity; it was just a matter of practice, half an hour of Taoist loving.
When a man loves once without losing his ching, he will strengthen his body. If he loves twice without losing it, his hearing and his vision will be more acute. If thrice, all diseases may disappear. if four times, he will have peace of his soul. If five times, his heart and blood circulation will be revitalised. If six times, his loins will become strong. If seven times, his buttocks and tighs may become more powerful. If eight times, his skin may become smooth. If nine times, he will achieve longevity. If ten times, he will be like an immortal.
When both parties are as spiritual as immortals they can unite deeply without motion, so ching will not be stirred. At the same time the couple should imagine that there is a red ball as large as a hen's egg at their navels. They can thrust very slightly. But if they get excited they should retreat. In twenty-four hours the couple can practise this form of union dozens of times. By practising this they can also live a long time.