[Suzerain of Sheol]

As far as I'm concerned, if someone is psychic, they can sense other people doing "psychic things" around them the same way... they can hear someone speaking around them. Some people have better "hearing" than others, but unless the character is specifically "deaf" there's no reason they wouldn't be able to sense others under normal circumstances, people specifically hiding their presence excluded obviously, though just like a silencer on a gun, there'll still be *something* there unless... they actually shut off their psyche.

Ctrl+F and replace psy for spirit in there as well.