Pretty much a duplicate thread of another one, but I'll post here anyway because I prefer this one.

All Dissipation needs is a different effect for each of the two fairies.
e.g.
Dissipation on Eos: Restores 3 Aetherflow stacks, up to a maximum of 6. Increases healing potency by 20% for 30s. Fairies cannot be resummoned for 30s.
Aetherflow would continue to restore Aetherflow stacks up to a maximum of 3- that is to say, the only way to obtain 4, 5 or 6 Aetherflow stacks is via Dissipation, while already having Aetherflow stacks.

Dissipation on Selene: Restores 1 Aetherflow stack, up to a maximum of 3. Reduces global cooldown to 2.0s, before spell speed effects, for 30s. Fairies cannot be resummoned for 30s.
The point of this is to simultaneously allow its use for an emergency stack of Aetherflow, but also to boost healing as Dissipation should, and/or boost DPS, as Selene should.

Of course, I'm not saying these are perfectly balanced or what-have-you, merely that Dissipation should have separate effects for each fairy, considering they do different things. Seems lazy for an ultimate ability to sacrifice the DPS fairy only to increase your healing, but not DPS is any manner whatsoever.