Yeah i do. At times i find it easier to do it up than down...
sex is like being with a bank, once you withdraw you loose intrest.
I tend to do them upstrokes and brushing my middle finger on the string on the higher strings, and downstrokes on lower strings.
^^^ same, up strokes 4 higher notes and down for lower, varies occaisonally to fit with into a rythm or summat but yer...
There are probably different, more orthedox methods to doing it, but here's how I go about it:

Say you hold your pick parrellel to the strings. Rotate the pick downward so your thumb is pointing towards the floor and your pick is now perpendicular to the strings. With this posture the plucking point of the pick is now before a large portion of the flesh of your thumb. When you pick the note, brush this flesh against the string.

Basically, your still hitting the same spot on your thumb as you would with a down stroke, but with your pick and thumb tilted, that spot is now "behind" the picking point of your pick - get it?

Schecter C-1 Classic (Antique Amber)
Ibanez JEM 7VWH
Crate Palamino Class A tube combo
Digitech RP80 Multieffects pedal
Ibanez TS9 DX Tube Screamer