A Risian term for a sexual encounter freely offered to visitors, which a guest signals an interest in by displaying the fertility statuette called a horga'hn.
Jamaharon is a custom of the pleasure planet Risa. A visitor who displays a horga'hn, the small carved Risian symbol of fertility, is understood to be seeking it, and Risians respond readily.
The term is introduced in Captain's Holiday in 2366. William Riker asks Jean-Luc Picard to bring him back a horga'hn from his enforced holiday, without explaining what it means. Picard, trying to read in peace, puts the statuette beside his chair and is puzzled by the stream of women who approach him.
Risa and its openness return in the Deep Space Nine episode Let He Who Is Without Sin, where a puritanical group campaigns against the planet's ways, and in Enterprise and Lower Decks.