It doesn’t mean anything, Collins was just making up words to go along with a rhythm track, and that is what he came up with that fit. He was planning to find a real word to replace it, but ended up just keeping that lyric.
David Byrne told a similar story about the Talking Heads album “Speaking in Tongues”, saying he just made up nonsense words to the songs at first, and later replaced them with real words that fit.
I saw Hoyt Atkins on TV telling someone how he wrote the lyrics to “Joy To The World”. He said he had written a piece of music that he was trying to sell to somebody and the man told him that he could not judge the music without some lyrics to go with it, he told Hoyt to just make up some nonsense he could sing with it so he sat down and the first thing he thought of was “Jeremiah was a bullfrog, he was a good friend of mine” and the rest just naturally followed within five minutes or so. He sang it for the guy and he said something like, “That’s a hit song, don’t change anything” and the rest is history.
I saw an interview with Gregg Allman a while back, and he told a similar story about the song "Melissa." He said he had written the lyrics and the music but didn't have a name for the song for a long time because he couldn't think of a girl's name that sounded just right in the refrain line. The song was actually called "Delilah" for a while. But Allman said he was in a grocery store and he overheard a woman with a Spanish accent scolding her young granddaughter ("Stop that, Melissa!") for running around and pulling things off the shelves. He had a brilliant idea right there on the spot that the name "Melissa" would fit perfectly in the song, and the rest is history.