How do you do it from the side?
 

It looks so easy but I can't seem to pull it off. Any suggestions?

You can just spoon.

If her hips are too big, just stick a pillow under your hips

Yeah, pillows are key in any "on the side" position. Ya just gotta get lined up good, otherwise somebody has to learn to levitate.

if you can't stay in for whatever reason (big butt, small ding-dong) you can rotate your body out a few degrees from hers making it a little harder to be all cuddly, but easier to maintain penetration.

From the side how? Facing towards her front or back? Never done it from the back, I find eye contact almost completely necessary. Can't get as deep from the side, but it's very relaxing. It is also difficult. I wish I had some good advice, but basically just have her raise her top leg slightly and do your best. It's like learning to whistle; hard to explain, but once you get it the first time, it comes very much easier.

i've never done it facing her... never sure where to put her leg... going from behind while on our sides makes my job easy, and it gets her off quite well.

we're positioned basically doggy style but on our sides. very little movement on my part is quite enjoyable for her. so it's good for the both of us.

Doggy-style on your sides is great fun. Works best if she's shorter than you, since you have to move down to get the fun parts all lined up. Imagine she's sitting on your lap, except you're on your sides. If she's too tall, you end up seeing a lot of back. A bit shorter and your heads line up too.

Then add some kissing on the back of the neck, mandatory grabbing of the bobbies, and if you can pull it off she may enjoy you wrapping your hand around and playing with her clit while you are doing her from behind.

Ahhh.. great position. Don't usually try this one if you have a super hard erection though, works better when there is some "give" or "curve" and the penis isn't trying to snap back into pole-form.

Oh yes, also much easier if you can find a wall or something at your feet to push off from. Otherwise leg cramps may result :-)