This meme is pure nonsense gold. The phrase "On a weela, Ona Wissitonawayeaa" is that perfect kind of gibberish that just sounds hilarious when you say it out loud.
It works best as an audio overlay on a video of someone doing something unexpectedly clumsy or silly. The random, sing-song tone catches people off guard. You can use it as a reaction to a friend's awkward moment or any clip where someone is just vibing without a care in the world.
The humor comes from the complete lack of meaning. It's the perfect sound to make when you have no idea what's going on but want to be part of the fun. Just let the weirdness flow.