A phrase used to express when you'd like for someone to do something, but you don't want them to feel pressure to do it immediately or to feel burdened by it; rather, whenever they have the chance or if they can. It is also used to express when you're not intending to pressure someone or to soften a request you have for someone so that it doesn't feel hard, harsh, or demanding. It can also be used sarcastically, in an event when there really IS pressure to so something. Hey, call me whenever you decide. No pressure.

It would help if you could give a context.Usually we use this to say we are not forcing someone to give a reply to something they have suggested.Without the context it is difficult for me to give you a better answer.