The pronunciation of the characters 'to seek' 寻 and 'to sink' 沉 in the Cantonese dictionary are identical, tone and all, both pronounced chàhm (chum). There are even different views between lineages on which is the proper character to be used in the name of the second set Chàhm-kiùh 寻/沉桥 because they sound identical.

However, when the character 'to sink' 沉 is used to name the deflective action chàhm-sáu 沉手, I often hear people (at least westerners, and this may be the reason) pronounce it as 'jaam' which is actually the pronunciation of another deflective action, 'to chop' jáam-sáu 斩手. This is the top half of the two-arm action of gāang-sáu 耕手 in isolation, which brings up another question; whether it is proper or common among native Cantonese speakers to not pronounce the final G here, as most people in WC pronounce it as gāan-sáu.

As for the character I'm looking for, it is the Fatsaan dialect term for the deflective action commonly called 'pressing hand' gahm-sáu (gum) 揿手 with a similar meaning. It is the preferred term in WSLVT and often phonetically spelled by Sifu David Peterson as 'soh sau'. The only character close to that meaning that I can find in the dictionary is só 锁 meaning 'to lock', but I'm not convinced that is the one.

I was just in Hong Kong two days ago and forgot to ask there.

Any comment, confirmation, or correction on these would be appreciated!