Mine is a Doc Johnson one I got from Amazon. It's double opening is one for vag replication and the other a tighter anal one. I just wack some lube in and away we go!
Your sleeve is different from mine. Mine has no opening at the end so I get to stroke using my cum as a lube. The other sleeve that I own is a simple jelly tube./ I'm sure the narrow opening adds a great deal to the enjoyment
It's great, wish I'd discovered it sooner. I folded a hotel towel around it once and then a pillow and fucked it rotten. Fuck knows what the maid thought when she picked the towel up.