How to stop a Banshee?

Right. She's only angry because all of the gamers that mistreated her in the campaign. Single player scrubs

Headbutt her - it usually stops screaming women.

With melee, obviously

Does she also try and put her fist through youre chest?

Its hitscan powers, IIRC. Projectile powers get blocked, hitscan powers don't trigger the hand of denial. 

bsn.boards.net/thread/19654/research-incendiary-banshee-breaching-praetorian:

Banshee breaching

As we know, in order to stop a Banshee, a certain amount of damage needs to be applied in a certain window of time. But as it turns out, what counts towards this threshold is not the real damage the attack dealt, but the damage it would deal to organic health (QME takeaway: start with Incinerate and a fire explosion). Known exceptions (non-exhaustive list, may be updated if something new comes up):
– Disruptor ammo counts normally against barriers
– Smash counts normally against armor

For the record, the thresholds are 4000/6000/7000/8000 dmg in 4/3.5/2.5/1.5 s on B/S/G/P, halved in solos. This means that stopping a Banshee in a Platinum solo requires far less damage than on Silver with a team.

lull her into a false sense of security, love that strategy- now you've got her right where you want her! 

Hm. An actual solo mechanic. Now I can legitimately bitch at joiners that they got me killed by making the Banshee harder to stagger.