A similar one to this, but bought at Target (Deco brand but same picture):
Image: Quality Double Flocked Air Bed with built in Sponge pump by FUN ZONE
The package didn’t contain instructions. The way the pump works is a bit awkward and, for a while, I really wasn’t sure it was working. Went online looking for instructions. Closest I came to helpful advice was this Amazon comment. It eventually did work but it took a while and I’m thinking that maybe, just maybe, I didn’t do it properly.
What I did: took off the cap and valve from the pump and pumped using my bare foot making sure I was covering the hole with my foot while pressing the pump and letting air in while lifting my foot. Because the sponge pump sends the air in other parts of the mattress, it’s hard to see that the mattress is in fact being inflated. There are two other valves on the mattress but they seem not to be used while inflating the airbed using the pump.
It might have taken me less time blowing the airbed with my mouth, especially given the time I spent looking for instructions. After all, I’m a longtime sax player and a lifetime non-smoker. My lungs are working properly.
To be honest, I did feel rather silly being unsure as to how this inflator worked. And I’m not completely reassured. Guess I just became accustomed to reading detailed instructions, even when they’re insufficient. Even a single diagram without any word would have been quite useful.
Now, we need to find out how long this will last as a mattress. We plan to use it as our bed until our furniture comes in from Montreal, which might take a few weeks. Hadn’t noticed the comments on the Target.com site saying how this airbed may deflate after just a few uses. The box does include a small puncture repair kit. Let’s hope it won’t be needed under normal conditions.
Disparate 
you are officially my hero, and my friends’, thanks for the protip, it all makes sense now, internet kudos to you good sir.
Glad this was useful. Inflating an air bed shouldn’t be difficult and it looks simple, but it’s not obvious.
dude thank god for you ! all the way over here in engerland we were standing around trying to figure out how this darn thing works…. duh! you take OFF THE VALVE CAP… yeah, simple diagram would have helped. THANK YOU and thank god for the internet.
This is exactly the reason I wrote this post. Glad it helped!
@Cindy Not sure what a CPAP machine is but if you have an inflating device, it does make sense to use it. The sponge pump is convenient because it’s embedded in the air bed but I probably should have used something else.
Thanks!
I used my CPAP machine to inflate it…took awhile, but better than the sponge pump. lol
So, the main issue is making sure you cover the hole when you pump…
I cant do it!