I been thinking up a couple combinations. So far my favorite:
Support item:
Gives AP to stack W passive, ability scalings just a bit more, and 50% mana regen for
passive.
Keystone: Aery, gets used when you W, used for poke when stacking spellthief, and protects the heal you give to ally.
Masteries: flowband, transcendence(optionally absolute focus), gathering storm. I take future market(i dont get to use biscuits, i barely get to use the 2 health pots) and 5% cdr. ~I considered ravenous hunter with poro, but not sure.
Spells: Heal Exhaust if ally takes tp/heal. Heal Ignite if they take Heal. I have considered TP, but not sure.
Ability Order: Q > E > E. Max E, put a point into W when you have to, max W, then max Q. Q is only for the support item and slow.
Boots: I just dont use them.. I think yuumi is so useful with so many items, which is why the next part is long. You can optionally take cdr boots if you want, helps with transcendence.
Items:
, then
. As mentioned before, athenes +5 ap per 25% mana is pretty nice for W.
adds healing, active, and 150% mana regen. Thats a big number! Landing Q gives a bunch of Athenes stacks too, so you can Q E, land Q then E again and proc athene twice.

: you can take this if you believe your ally wont run it down and if you can stack it, further buffing W.
: wow. Does this give ap. More Ap for W, also increasing with athenes mana regen items. Yuumi ap per level is surprisingly high btw. Its especially good with allies that build a lot of damage themselves.
Other possible items i wont go indepth with: (Mostly because my games dont last long enough)
