<p>I once made a melted patch on a fleece jacket with my sb-800. I'd put it face-down, whilst at 90 deg, ready-to-fire light 'on', turned my back and it fired. Sadly it was on full power manual...:-(</p>
<p>Reason it went off, well Oops, I was on slave trigger feature and fired the D300's pop-up inadvertently. I heard the 'pop' behind me, spun round and when I lifted the flash there was a small puff of steam and the surface had gone a bit bobbly. You could feel the melted fibres all crispy and they'd gone a bit darker. I'd only rested it on my fleece to protect the glass front!</p>
<p>I <strong><em>really</em> </strong>don't advise it, but you too can 'Feel The Force' and see the steam if you fire it in contact with your jeans leg. I suspect this would very rapidly overheat the tube, but an accidental <strong>ONCE</strong> has seemingly had no ill effect on my 800 and that was about 4 years ago.</p>