'Tites go down, 'Mites go up. Just like the stem of the “T” goes down, and the “peaks” of the “M” go up.
But chocolate in any case.
I always remembered it by tites have to hold on tight 'cause they’re on the ceiling. But your way is cooler.
Heheh, I hadn’t heard those mnemonics before.
But I had thought that Chronos’ point here was being amused by the mixed spelling - “stalgtite” being something of a mongrel word.
Stalagmites - from ground up
Stalactites - from the “roof” of the cave down.
My version of the primary school mnemonic was that the stalaGmites went up from the Ground, and the stalaCtites went down from the Ceiling. And that would be good to know, if, perhaps, they were things I encountered on a daily basis. Otherwise, well, who cares which, as long as chocolate is involved. 
I employ a useful mnemonic I first heard on a Mammoth Cave tour about 30 years ago. Stalctite is the name of the formations hanging from the ceiling because they must be held tight in order to stay up there.
It was my understanding that when they meet, they have a stalac-fight, but I am not a geologist.
For which we are all glad. (When a stalactite meets a stalagmite, they form a pillar, IIRC).
I use: c = ‘ceiling’ in stalactite, and g = ‘ground’ in stalagmite.
And to finish the mnemnonics, “mite” is like “mountain”. They’re both raised up from the ground to a point on top.
Celyn has a really good point about the chocolate, though.
That is rather “catchy” but it requires being able to spell. If you make up your own words that doesn’t work.
Chocolate is my favorite food group.