Option to always play with same color pieces ?

Wouldn't it be possible to do online ?  I could set the colour of my pieces to black and my opponent could also have black but my pieces can be programmed to appear to my opponent as white . 

I need this because after losing an intense match  , i always go for another match and if i get alternate color in back to back matches , i often mistake opponent pieces as mine . 

Just click 'Custom Game' from the normal game setup screen and choose 'I Play As' specifically as black or white.

There is no such option. I play on my mobile phone 

You can only choose color in unrated games.

I don't have the app, but if you play via a browser when logged in you should see the option (works for me). I'd suggest posting in the Site Feedback forum to request new features.