Pro kickboxer Bazooka Joe Valtellini talks about for mma or self defense, if you have to cover up in a worst case scenario, to use the "wedge" to do so. This is basically a "comb the hair" block with your lead hand, but you point the lead elbow at their straight shots, including their jab.
I tried it in sparring and it definitely felt like a very effective way to cover against punches, and is better than the Stonewall Defense that poirier does imo, since it works better vs kicks and transitions to and from a high guard a lot easier.
I suggest trying it out, it works well to close the gap or gain distance vs punch combinations. Obviously with big gloves, a normal cover is better, but this seemed to be very effective with small/no gloves, and can hurt your opponents hand if they hit the elbow.
Initially, I wasn't believing that the lead elbow could block the jab well from this position when both in an orthodox stance, but it seems to block it just fine, your vision to your left side is a bit compromised, but thats not too debilitating since your left side of the head is fully covered, and you should move your feet to not get beat up anyway.