Help With A Pumping Routine Using Bathmate

I’ve been doing PE (mainly with an extender, manual stretching and clamping) for 3 years now. I’d really like to try and gain more girth though - so what would be a good start or routine (using a Bathmate Hydromax)?

I’ve tried using it before (3 sets of 5 minutes), but I always end up getting a swollen/engorged foreskin. Is there any way ‘round this?