I have a cousin whose visted for the summer, & she is.... *sigh* she's 4 & her name's Amiyah & guess what every time she vists she has to spends at least one দিন at my house, & she vists atleast 3-6 times a year.
আপনি can just go to a different room and do what আপনি do for fun and ignore him/her. Go hang out with বন্ধু অথবা do something fun at home, something that keeps the time passing faster until your cousin leaves. আপনি have to be calm and don't pay attention to the annoyance. If it's hard try to listen to সঙ্গীত and pay attention to the music/song. Turn on your fave song and pay attention to the words. If if this annoyance makes আপনি angry just take a glass of ice cold water and drink it all then do something আপনি do to pass time faster. That's what I do when I am annoyed and it actually works. :)