Our male cat does it too - he's 8 kg! When my husband is laying in bed watching TV or reading, Fister will climb on his chest or stomach and make himself comfortable. If a book or some papers are in the way, Fister will give him "the look" and is very annoyed, but eventually Fister wins. He never comes to lay at me, but when I go to sleep, he immediately comes over and lay on half my pillow. By then, he feels sure I won't move around too much!