Welcome to my Button Mashin' Sona build!
The Idea behind this idea is that activated items are more impactfull in team fights and alow for more map control. ADC's and the sort can't build as many activated items because they are always attacking and positioning but as a support in lane , you do very little attacking unless it is against enemy champions.

The activation items for Sona give her a decent amount of AP as well so her abilities don't suffer from lack of power, and sona doesn't have so many CC abilities (except for Crescendo) so these give her a lot of slows.

I find for many supports that it gets quiet boring, because you don't press so many buttons unless you are engaging and when you in cool down you position and defend your ADC (this is also a reason I hate playing as ADC). With the Button Mashin' Sona build I am constantly pressing buttons, activating abilities and items. it makes it so much more fun!

Have fun!
please comment.

An interesting question. As many supports I like taking Money Quints (which i heard you can't buy anymore...) and focus on ability power armor and health.
Masteries is also an interesting question, i usualy go for something like 0,9,21 or 4,5,21. focusing on money and cooldown reduction of items, as well as health and resistances in defense.

The Items I buy follow a few simple rules:
1. Activation Item!
2. Passive Ability Power and/or Cooldown reduction.
3. Slow or heal.

I want to buy activation items so I can click more buttons and be able to respond to any event. The Items I buy are either healing activation items or slows that give a passive AP or cooldown reduction, which helps sona with the effectiveness of her abilities and the rate at which she casts them. Sona spams abilities even without these cooldowns but with these items she will always be pressing buttons, either her own abilities to heal and speed up out of combat, or attack during combat while slowing the enemy team and healing her own.
With all these activations, you wont have time to activate them all before your team comes out on top.

During lane upgrade your Q first for extra poke, then W for healing. I get the move speed, E, early either at level three if we are winning lane or four and level it up last.

Pros: So much fun spamming out abilities, slowing your enemy team and gaining control of the map almost single handed, if there was no fighting you would win without your team ( not such a supporty thing to say but i like playing carry supports = supports that carry the team except for damage output). You have a rediculous ability to chase enemies or disengage with Frost Queen's Claim, Twin Shadows and Power Cord Song of Celerity (E).
Cons: Health! the only Item that gives health is the Sightstone ( and maybe the Locket) Sona is very squishy alone, these items don't help much. If you can correctly position yourself in team fights this isn't a serious problem just make sure your engage is very fat and tanky. If you aren't focused in team fights (because you are a support) then your team will be at a greater advantage because of Sonas many Auras.

Button Mashin' Sona allows you to gain control of the map while hunting down enemies with a nice amount of slows while letting your minions push lanes. The AP you get is ok for a support but the utility you bring to the team is unmatched by any.

Hope you like it!
Try it out for yourself and comment below!