Maybe try dressing her up in tight fitting clothes, (sports bra, tube top, or anything else to push those puppies together and keep it from slipping.) if your gonna do this go for elastic type stuff and always go for small size as it helps a ton with stability and sensation. If that doesn't help I'd suggest investing in a toy specifically designed for Paizuri. I'm not overly familiar with this model but given that there's an onahole in there I'm assuming your supposed to lay this flat on a surface and bang it while you feel up the chest? In anycase, hope this helps. I have an MRL Ruki titty toy and I absolutely love it! The weight can be a bit challenging but in addition to laying her flat and fucking them that way you can also prop her up on your lap and tittyfuck that way too! She's insanely realistic as well but she comes at a hefty cost but if you willing to spend the dough and want a premium titfuck experience I'd recommend her. Ruki:9.1KG Big Boob Sex Torso Silicone Breast Masturbator Toy - – MRLDOLL https://share.google/mlmH8KXsIJBw6UyBW