pf2e.fyi
From Pathfinder Lost Omens The Grand Bazaar, which isn't enabled.

Siphoning Touch

FEAT 8
ARCHETYPE
Archetype Spell Trickster
Prerequisites Spell Trickster Dedication; ability to cast vampiric touch

When you cast Vampiric Feast, you can modify its standard effects as follows: Instead of gaining the temporary Hit Points yourself, you can grant the temporary Hit Points to an ally within 30 feet. After 1 minute, the ally loses any of these temporary Hit Points that remain.

Pathfinder Lost Omens The Grand BazaarOGL