I have experienced sex with a tantric healer. It's not really a 'delayed' orgasm.
Tantra is being present in the moment and loving fully. As sex goes, it can be explained as more of a full being orgasm that does not include male ejaculation. There is a definite orgasm...a build up, a release...but with a tantric practioner (male) there is a climax without the actual spilling of fluids. 
The most important part of tantra is unconditional loving - and being awake, alive and open to the present moment.
Tantric sex is very delicious.
