Thanks for the tips, I was already using both hands as I'm playing on my phone (I play games like this mostly for the experience and not for the scenes), and I always milked her when she was full... so I guess I just need to be faster.
doing it on mobile definitely isn't going to get you the fastest time. The game was built around a PC aspect ratio, so keep having to scroll up and down on mobile and it'll lose you time whenever you do.