Apple’s Touch ID technology is capable of recognising your fingerprints in a split second, but what about all those other parts of your body that you might (or might not) want to use? Could you use your face? Your elbow? Your nose?

I’m ashamed to say that Alphr hasn’t historically performed these kinds of exhaustive full-body security tests as part of its smartphone and tablet reviews, but it’s becoming clear that these are the important questions that everyone needs to know the answer to.

Thankfully one user over on Reddit (thanks, A_Gigantic_Potato) has gone where no Alphr reviewer has gone before and taken the time to rigorously benchmark the Touch ID on his iPhone 6s Plus with every single part of his body. Oh, and he was using iOS 9.3.2, just in case you’re keen to replicate his findings on your own iDevice at home.

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The body parts which DO work with Touch ID

Fingers

Palm of hand

Big toe

Index(?) toe

Pinky toe

“Palm” of foot

Nose (very difficult)

Back of index finger (very difficult)

Heel of foot (works better than thumb imo)

Left nipple (right refuses to co-operate)

The body parts which DON’T work with Touch ID

Forearm

Knee

That round bit of your ankle

Belly

Earlobes

Eyelid

Thigh

Right testicle

Tip of penis (underside)

Tip of penis (top side, although it’s interesting to note that this generated the best results although the results seemed to deteriorate and got more errors as it got flaccid)

Nipples do in fact work pretty well. I was trying to test my right one but it must be faulty because only the left one registered.

Well, so now you know just how versatile Touch ID is. Thanks, Reddit. And if you were thinking about buying a secondhand Apple device with Touch ID – well, you may now be having second thoughts. I know I would be.