It really is amazing how something so small can make such a big noise... constantly. Indigo is definitely in heat and has been going at it hammer and tongs in her bid to attract a mate. You can hear her from outside, through a closed window.
Theo, who was slightly later than he ought to be neutered, and who seems to have the urge if not the ability, has been spraying everywhere. I suspect this is attempting to give Indigo 'sexy' messages, but Inds isn't fooled, he hasn't got the bits to smell right any more! My house on the other hand is decidedly less than fragrant!
Poor old Theo, he does try... he lollops after her like an overgrown kitten and he's even straddled her a couple of times(unless she smacks him first) and then... doesn't know what do. Poor old clueless Theo!