I believe this is the next step in wc training after you have become a bit proficient in the basics. The basics are: dan chi sao, lap sao, luk soa, basic stepping, drills using wc moves againt various attacks.
After you have spent a few months doing the above it is time to apply it from a distance against non-wing chunners This is not a "wc people need to spar and spar against other people" thread. This thread is about diversifying wc. WC is a specialized system that was meant to be added to regular fighting(kickboxing) or that regular fighting was meant to be added into wing chun training.
One of the major things I learned from sparring was that you can't survive just using the wc blocks/parrys/ strikes. It's impossible! The mentality, and I believe it was well intentioned, was to train a few movements to master them. Train fook, lop, bong, etc and be able to blast people away because that's all you do. The problem is that those only work at a certain distance. At other distances the covering seen in boxing/kick boxing work better. And still at other ranges(grappling) none of them apply as they are done in the form or when trained against strikes. Sure you can say that when you throw someone your hand was in fook so you used fook but in reality it wasn't fook.
Tneihoff would disagree and say that wing chun is attached fighting. I don't disagree or agree completely. Enter, strike, grapple is the basic strategy of many Chinese martial arts. WC seems like it has good simple tools to parry and enter. Common wc training needs to include more power training and not just the typical wc jab which could be powerful but often isn't.
I was sparring the other day and the purpose of this was to work in wc trapping(entering). The other guy would punch me with medium power and I had to try and stop his hands from moving to strike him. What happened was a lot of hilarity. It worked ok sometimes but other times against the craftier strikers I got clocked. Even though the drill was to work on the trapping aspect I learned that it is impossible to trap ALL strikes coming in. Covering with my arms while using angling footwork would have worked well WITH the trapping. I think the trapping mentality comes from the wc way of thinking where when you get it the opponent is finished. But during sparring the opponent gets trapped up and hit...but them moves and it starts all over again.
What I noticed about my training brothers, as well as others on youtube, is that they stand robotically with their hands out to meet. There was no head movement and flat footwork. When the sparring started then the trapping hands would fly into action sometimes missing completely allowing them to get hit. Constant forward pressure worked sometimes and other times it lead to getting hit rather hard as you are walking into a punch coming at you.
This is just a log of sorts for my sparring adventures. Are wc opposed to adding boxing covers and slight head movement into wc? Years of chi sao didn't prepare me to eat my friends right hook. I think he killed a part of my brain.