How to co sleep with newborn and toddler?

This question isn't specifically related to breastfeeding but I'm coming with a follow up question from a recent post about co sleeping.

My 15 month old and I co sleep but I would like to start trying for a second baby soon who I will need to co sleep with when he/she is born. I know it's not safe to sleep with a toddler and newborn together but I can't imagine getting my first baby out of my bed. How have you managed this ?