sorry but your friends and idiot... thats terrible advice... dont do that... not at all... you can safely give your plant 24-36 hours of dark going into flowering, but 5 days is completely asinine... no it wont help the female cause... you are not gonna get more females doing this... i dont know exactly what that much dark would do, but it wouldnt be anything good...
secondly if they have vegged indoors their entire life and arent hardened off to the outside its likely they wont make it... plants that are started indoors but are going to be moved outdoors need to do so slowly a little at a time... outdoors is a lot different than indoors.. natural sunlight is a lot different than hid or floro light... so if you havent already start getting them used to being outdoors...