I know there has to be someone else out there with this problem. I can reach most of the areas myself, but not evenly. So what’s the answer, and please, no hump jokes, okay? 
Thanks
Quasi
Of course everyone has the same problem… but it’s a great problem to have! Imagine… you’re at the beach, it’s a hot sunny day, you’ve just put down your blanket and are ready to lay out when you realize you need some help since you can’t reach your entire back and it’s the perfect opportunity to strike up a conversation with some nice looking stranger… who is also alone… with the line “I’ll do your back if you’ll do mine”. It works like a charm for both guys and gals since putting lotion on someone else’s back isn’t a huge deal and it’s a great way to meet someone (even briefly) who normally wouldn’t give you the time of day…
A lifeguarding colleague of mine can ‘lube’ his entire back himself. Must be a combination of long arms and flexibility.
Time for an application of some of my most obscure knowledge, gleaned from my days as an art student studying anatomy.
One of Leonardo daVinci’s lessons in anatomy for artists was the proportions of the male vs. female bodies. On the female body, the widest spot is the hips, but on the male body, the widest part is the shoulders. There are spots on your back that men cannot reach but women can. So I can tell the OP was written by a man.
Verify this for yourself. Put one arm up above your shoulder, and one arm down, behind your back. Try to hook your index fingers. Women can do this, men cannot. I’ve tried this on many people and I’ve only seen one man who could do it, he was double-jointed and had to dislocate his shoulder to do it.
Sorry to burst your bubble, but I am evidence to the contrary. I, too, can hook my index fingers together behind my back, and I am not couble-jointed by any stretch of the imagination. I also have very broad shoulders and am pretty athletic. I’m also an ROTC cadet, so it may be that I do more stretching than the average person, but it’s definitely not a freak occurance for a male to be able to hook his index fingers behind his back.
I do Hap Ki Do, and most of the guys in class can hook their hands behind their backs, and some of their backs are HUGE. (I love my class…)
Incidentally, I can hook my hands behind my back as described, and then straighten my arms. Yes, this is as freakish looking as it sounds - my fav. party trick. (Well unless the party is really rolling, and then I slap my ankles behing my head, but thats a completely different topic altogether…)
Al.
I think Leonardo was making a gross generalization…
My chest measurement is bigger than my hip measurement, soooo…, unless I’m freakishly deformed (I’m not, as far as I’m aware), my shoulders are broader than my hips.
I don’t know, man. What if she says her back’s already been done, or what if it’s some guy named bubba whose belly is a planet unto itself and he gets the wrong idea (that scene from Deliverance comes to mind)? Nah, I think what I’ll do is spread some Saran Wrap on the bed, cover it in sunscreen and wallow around in it before I’ll ask someone to “do my back”.
Any other suggestions?
Quasi
I can shake hands behind my back… but I only developed this skill after heading to the beach for an entire summer.
Since the beach was fairly close to home, I always put on sunblock at home… looking in the mirrors to make sure I got everything. After a couple weeks I was able to do everything easily. and nobody thinks I’m flexible.
I can do my own back - which is good because it has so much hair, no one else would want to!
You could just wear a shirt. A nice cool shirt would do better protection.
Quasimodem, you could probably get good coverage attaching a sponge to a back scratcher. I think the t-shirt is easier and have a couple of cut offs just for the pool.
Jois
I can also disprove Chas E. I’m a male, and can do the finger hooking thing. Oddly enough, though, I can do it with my right arm up and left arm down, but with my left arm up and right arm down, I can’t quite reach. I guess I’m just asymetrical. (I’m a righty BTW).
As for the the sunblock thing, the “I’ll do yours if you do mine” thing sounds like it’ll never actually work unless you happen to be stunningly attractive. Luckily, I’ve got a girlfriend for such things, but before I did, I’d just do the best I could. Between both hands and going over the shoulder and under the shoulder it wasn’t a big problem.
Ron
I usually just squirt some sunscreen onto the wall, then rub my back all over it.
I can hook my fingers behind my back too, left hand up or down, I am double jointed, but my shoulder just barely starts to pop out.
One of the foam toilet brushes soaked in sunscreen?
A three foot piece of platic wrap covered with it, used like a towel?
Ask someone uglier than yourself to rub it on?
I used to have this problem when I worked outside all summer. I used a sponge attached to a long-handled wooden spoon. I cut a slit in the sponge and inserted the spoon. You could secure it with glue if you want. Just put sunscreen on the sponge and rub. Looked stupid, but worked really well.
I also can do this, and have been able to ever since I can remember. Interestingly enough, I’m also an ROTC cadet…I’ll be commissioned in July.
Jman
In yoga, the “hooking fingers behind the back” maneuver is called gomukhâsana, the Cow Face Pose.
When my yoga teacher first told me to do it, I found it just about impossible. At my farthest strech, my fingertips seemed a mile away from each other. But I kept up with yoga stretching, and over time it became possible. I also find it much easier with the left arm down and the right arm up. Because I’m slightly asymmetrical, my right shoulder tending to be a little lower. If it were any worse, it would be called “scoliosis” but I’m not calling it that.
Now I can wash my entire back in the shower all by myself. All you need to do is learn yoga, including gomukhâsana, and you will be able to reach every spoton your back. It brings a great many other benefits for your whole life, in addition to self-applied sunscreen.