deriv LSK ETT STT aSTA ALPH OLDHOMEPAGE NEWHOMEPAGE
To make the hiss sound, open everything, mouth and throat and all, inhale deep, and raise you elbows some. Then relax suddenly. Some air will go out, hissing a bit. That sound you hear is a Sanskrit /H. You can also make it easily without so much gymnastics.
/pANini calls this sound visargaH विसर्गः or visarjanIyaH विसर्जनीयः, "outletting". I call it the hiss.
It is NOT the same sound as the Sanskrit h ह्, which is a voiced sound.
The H ः sounds sort of like the English H, while the h ह् does not.
Many people nowadays invariably add an echo vowel after the hiss. This is likely to be not PC, but you may do that if you like.