Stupid question but I can’t find online what is flashing of nodemcu. How to do it is available but why would you do it?
Apparently you haven’t heard of Google 
what is flashing nodemcu - Google Search
“Flashing” (AKA, uploading, programing, etc.) is when you transfer whatever program (AKA sketch, firmware, code, etc.) that you or someone else has written, into a MCU device’s memory. You do it so that your MCU device does something besides look like a big old bug on your table.
It can be done with device or processor specific software that differ based on the language, etc… In the context of what we predominantly use here, it is done via the Arduino IDE when you press the upload button (after you add in the ESP/Arduino Core into the IDE, of course 
so that the IDE knows how to handle the ESP based MCUs).
I guess I didn’t search very well. Thanks alot!. So basically every time I upload a code to the Nodemcu via the arduino ide, I am flashing. Oks. So we don’t need to touch the flash button on the Nodemcu yea at all