It's has been 20-something years, and i am too shy to ask in real life

Shall i

1) Move the stick like a "Z"

2) FORWARD + Quarter Circle to DOWN + Quarter Circle to FORWARD

3) Move Anti-clockwise from DOWN to FOWARD to CENTER to DOWN

just do a hadouken twice, without pressing the punch button the first time, that's how it is to me.
and i just slide my fingers around , and if it is a stick, its the same.

forward + fireball

 I suck at fighting games , a Kikou Ken is the best I can do :P

The easiest way to describe it is a Z.

You press FORWARD, then you make a straight diagonal line to the DOWN BACK direction, and then from that location you do a half-moon motion to the DOWN angle and continue it to until your stick is positioned directly FORWARD. And then you press the punch button.

If your oppononent is to your right:

1) jam the stick right
2) from that position, jam it diagonally down and left
3) do a counter-clockwise circle until the stick is once again fully pushed to the straight right.

Forward Down Forward,or Forward,fireball (fireball being Down Forward).

At first, I always thought it was just like a forward, then hadouken, but now i just wedge my thumb in the crevice and then do a little meshuganuh.

Option 2.

wow i had this exact same problem, first time i ever played street fighter was 3DS, i glad im not alone :D

do the motion for the hoduken 2x in a row then press punch without releasing the d-pad once. I dont know about sticks, but i assume that it would be the same..