Opening up about sex

Hi everyone, so recently my boyfriend of two years and I have starting opening up about what we like in the bedroom. He recently started telling me he wants to try anal, and I’m all for it. We want to spice up our sex life and make it fun again. My question is, does anyone have any tips to get started? We’ve tried it a few times and it always end in pain on my end(haha) and we need to stop. What can we do so we can have a pleasurable experience? All answers are welcome!!