Ah, yes they are. Perhaps they are not "native" to what your teacher is doing, but they are a part of WCK.
Sink, rise, swallow, spit is in ALL WCK.There has been argument that Yuen Kay San studied some Weng Chun or other elements which may be where he got them. Looking at his brother's lineage in Vietnam which has a hodgepodge of a ton of different CMA I'd be inclined to agree that's the source.
It's lut sao jik chung. Also, these two (the method and the kuit) both refer to the same thing -- how do you stay with his pressure? One way is to swallow it. How do you jik chung? One way is to spit. This is WCK 101.In LEGITIMATE WCK we use "Loi Lau Hoi Sung/Lut sau chi chung" not "Tun/tou."
Does that mean everyone who trains or learns WCK has learned it? Of course not. Most people practicing and teaching WCK are missing parts of the core curriculum. But just because you didn't learn it doesn't mean it isn't a part of the curriculum.
Interesting that your sihing (Alex/Duende) has pointed out that these things you believe are not a part of WCK are in fact a part of HFY's curriculum. This sort of refutes your whole argument, doesn't it? It just seems that YOU haven't learned it even though it is a part of WCK. There is a lesson there -- although I don't think you will see it.What a surprise, someone who doesn't even know the fist maxims of Wing Chun agrees with Hendrik. Good thing those presses are already stopped.
If Yik Kam Siu Lein Tao contained more Wing Chun and less O-mei and White Crane, we wouldn't be having this discussion. Then again, Yik Kam never called his system Wing Chun so I guess it's a moot point to discuss it as such.