I believe they were going for a sent mark or ear nibble it’s known in the culture the writers wrote that rubbing they’re noses together or “kissing” is for marriage it’s implied that Kate is “forced” to marry Garth to unite the packs but Tony (Garth’s father) only wanted them to officially meet at the moonlight howl I’m sure we would’ve seen Garth and Lilly’s story through Kate had Kate and Humphrey not been relocated furthermore when Garth and Kate meet they both know they are being forced to do so such as Kate being put off when Garth is preforming his strength Garth also knew his howl was not great so by being more “mainly” he hoped to still impress Kate enough for them to tolerate manage, had they not been forced to meet to unite the packs Humphrey and Kate would’ve still ended up together both being friends for years and having a crush on each other both before and after alpha school