I can speak about Theravada 'practices' a little. But I don't speak for Theravada or anything else. What is Theravada and Mahayana? Are they 2 separate things? There is a koan!
I've been in group meditations several times lead by Bhante Seelananda of Bhavana Society and other lesser known teachers. Basically, they teach to start with meditation on the body, of perceptions of sounds as just sounds. Like if you hear an airplane passing, it's not "an airplane." Realize it's just a sound.
I asked Bhante Seelananda about the Thai practice of the Buddho mantra, or of the counting of in-breaths and out-breaths taught by Ayya Kheema. These are a little like koans in the sense that they are thinking, thinking about impossible questions, or Buddho, or numbers.
The advice was, that this too is ego. When you are thinking about koans, or counting, or mantras how can annata 'hit' when you are clinging to koans, or numbers or mantras? There is a lot of self in thinking about a mantra or koan. What is it, the analyzer who thinks about mantras and koans? Is there anyone there? There is no one in you, to be thinking about a koan or mantra, only the sensation of the breath is real. That was the teaching of Bhante Seelananda of Bhavana Society. He seems like the stories of arahants in the Nikayas. You only need to see his countenance, or his manner of walking meditation as he walks to receive alms, to appreciate his understanding of the dhamma. He seems..empty. Really profoundly empty more than any other monk that I've known. He seems. there with amaravati. He is 'gone'. That was what his form, told me about koans, mantras, counting numbers. They just reinforce the idea of self. The futility of looking for 'you' who is to be thinking about koans, mantras, counting numbers when that 'you', does not really exist.
Who or what is typing this message to you now on Dharmawheel? Does nem exist, or is nem some glitch in an internet server that caused this message to appear in front of your eyes? There's a koan. 'nem' cannot prove whether "nem" exists or not. and does not care about the answer to the koan. It's the same, either way.
It's all fun too. Not to be taken too seriously. Everyone is maybe wrong..it's all uncertain. The Buddha set the example, and never clung to ideas like correct or incorrect, and dwelt right down in the muck of the uncertainty. Remember in the Nikayas, there were times when he stayed silent regarding uncertain topics. Like the koan, of "does a Buddha exist, not exist, or neither exist or not-exist after death of the body?"...He didn't bother with koans like that. At least, that's what the Nikayas say. But they may be false too!!!