You can also help them understand by mixing kisses with rubbing your cheek/nose/forehead over the top of their head, their cheek, or down their shoulders, just like cats rub against each other and humans to show affection. Also gently bonking foreheads to imitate the ‘I love you please pet me’ headbutt. Brushing & scratching at itchy spots for them imitates the grooming that cats who live together in colonies do for each other. Basically just try to find hygienic ways of imitating cat social behaviors, short of actual licking, lol.
My cat will touch her nose to mine & rub her cheek across my face, which allows me to plant a kiss on her cheek. When she’s sitting in my lap, she’ll tip her head back until I lean down and kiss or nuzzle the top of her head. I’ve even found her occasionally trying to imitate the “mwah!” sound of my kisses, where she’ll nuzzle my face and make little chirping “mah! mah!” sounds. Cats are pretty smart little social creatures; they’ll figure out how to speak your language, especially if you put in the effort to speak theirs.