I've tried some of the things that BalzDaBurgh mentioned.... not so much to increase the size of my glans, but more to simply antagonize it and to try to amplify its sensitivity. For instance, on several occasions I’ve let clouds of mosquitoes feast on just my glans by judiciously wrapping my dick and protecting the rest of my body with thick clothes and netting. I was hoping the mosquito bites would cause my glans to swell up and become ultra-sensitive, but aside from the twisted pleasure of seeing and feeling their stingers go in, the only real effect it ever had was to make my entire body feel itchy all over. Shooing them off before they had their fill and sucked their blood thinners back up (in an effort to increase the severity of their bites) made no difference. On one occasion in northwestern Canada I was successful in getting well over 100 mosquitoes to bite my glans, but still with virtually no local effect.
Likewise, I have put numerous different topical preparations like menthols, deep heat rubs and toothpastes on my penis. Some of those things can be pretty eye-popping if you accidentally or deliberately smear them onto the supersensitive regions just below the rim of the glans (the sulcus and further down), but again, they don’t usually have much effect on the glans itself.
The problem is that the glans is so thin-skinned and has such a large supply of blood, even when flaccid, that any irritants from stinging nettles, insect bites or topical preparations immediately get diluted and washed away by the blood before any local reaction can occur. As such, I've never been successful in creating an itchy welt or hive on my glans, say, the way a mosquito bite on my arm can. The only thing I haven’t tried is physically beating or whipping it, although I’ve been tempted. But even that too would only be temporary.
In short, I think the only way to ever permanently increase the size of your glans is by routinely pumping it the way others have described, or by using compression sleeves the way I have described myself. Either way, I think it is worth pursuing. Imagine having a glans as large as the one shown below. I think this photo is fake, because I’ve never seen any other similar photos of the same penis, but it’s images like this that personally keep me going and fuel my dreams.