Just before a significant event takes place between the realms.

yes and I read 2 possible theories for it...one was that their hands where shaking when the portal in TP was about to open

the other one was about the coffee being bad/poisoned

...as well as arms going numb in FWWM.

The left arms going numb is related to the ring, correct? 

I remember the coffee theory from way back when. Some kind of connection to Coop's coffee turning into scorched oil in the Red Room. 

The portal/realm idea makes more sense now. 

In season 2 does the shaking happen the day of or the day before the Miss TP pageant, and the entrance to the Lodge/waiting room opening?  His hand could be shaking because they are a day or two away from the dates on Major Briggs map?

Several people's hands shook throughout the series, including Pete Martell. 

I imagine it happens (a sideeffect) when someone gets close to the lodge

I was wondering if it had to do with either reaching/stepping into the portal (think Jerry) but not entering.  Gordon was reaching up into the vortex, but did not enter.

Adding up things: One Armed Man misses his left arm; Man From Another Place (the dwarf) says in the Red Room 'I am the arm' (FWWM) and above the convenience store 'With This Ring I Thee Wed' (FWWM); Teresa, Laura and former Dougie wear the Owl Cave Symbol ring. Laura Palmer's left arm (Teresa Banks also?) going numb; and Dougie's left arm (the 'old' Dougie, who was 'manufactured' in 1997) going numb when he is with Jade, straight before he is sucked up to the Red Room. A pattern manifests itself: could 'left arm going numb' be a sign that one's 'good' conscience can no longer protect one from the call of Evil/Devil/DarkLodge, induced by prostitution, drug addiction, gambling and alcohol (Dougie), i.e. the illegal realm?