help me with anal tips and advice please

My boyfriend really wants to do anal. And I really want him to also. we've been successful before but it was like when I just got out of the shower. well sometimes our schedules don't match up because we have 3 children also. so we can't rush to the room everytime I get out the shower. But when he tries it feels like fire on my butthole and it stings badly. once his head is in it feels good but that first "poke" hurts so I bought this to maybe get use to it and it's pretty and I thought he might like it. any advice on how to use this and how to make it feel good to me also the size is small.. but can anyone give me something to compare it too the size is: S:

2.76'"1.18'"1.18"