I find fafnir horrible for pressure. I dunno if it's even worth mentioning while we have GF frc.
But if you're set on using it for pressure you could be gimicky and try it in the corner. The guard stun might be useful there, and the guy might not expect it - you might not be poked out of it if you use it sparingly.
The push-out should make it difficult to continue though, so try an FD brake on your way back in to beat out pokes. Once you're in, 6P delay tricks, tick throw...bait a VV...I dunno pressure to me is just the route to a WT.
:\ Outside of combos I find it pretty useless. If you do manage to develop some solid pressure from it, that'd be great. I freaking like that move, but it feels so useless sometimes.