SUPPORT / HEAL / RESCUE BEAM ANNOYING VISCOUS

I like this order
Your fist is tempting to spam but you mostly want to save it for predictable strikes which displace the enemy into your partner (especially enemies retreating up stairs or by walls).

Skip to big purchases if needed, but this order should be fine.

Other support builds: Begrope Bebop, No Aim McGinnis, Gunless Ivy

Be annoying
This build does EXACTLY what you need it to
Your fist can move you, displace enemies, or adjust allies in your cube
You almost always want to hang back
If they get in your face, just run away or melee them since you don't do any damage otherwise
Keep in mind your cube at max removes debuffs but prevents ally ults from doing damage, and don't be afraid to sell Restorative Locket for counter items if you need them
Whenever your ult is up, look for any reason to go for split pushes or steal enemy farm
You shouldn't have more than 5 deaths in a single game, even if you're losing badly.