This is partly a question for Lovehoney, why no hollow butt plugs?
I have one that is a little too big for me still so haven't used one yet but they look interesting and there are none on LH? I'd be curious to hear if others have tried them or would like to see them in the store?
There's a lot of ones that are advertised as vibrating buttplugs that just come with a bullet vibe inside a tunnel or hole. Those might be worth looking in to.