She'll become much more affectionate and roll about on the floor.
Why do you want to know? Would love more background info. Best to have your cat spayed before she comes into heat. Don't make the mistake of letting her have 'just one litter' as there are too many kittens and not enough good homes for them.
If you have a cat showing signs of being in heat, KEEP HER IN. If she gets out at all, take her to the vet and have her spayed and aborted (sticky subject, but that's what I would do). Most vets won't spay a cat who is actually in heat because it makes the op too difficult.
Modified to say that I've read other of your recent posts and notice you have ragdolls. Are you breeding from them? Have you got the stud sorted. I'm not a big fan of pedigree breeding.