I'm looking for a replacement onahole for pic related, the wall is extremely thin on one of the sides of the sleeve that came with her and I'd rather not have it rip open mid session.

I'm a bit limited when it comes to the size as the bundled in onahole is 12cm long and 5cm wide. The plushie's pocket is about 18cm deep but it might not be able to fit anything wider than 5cm. Do you guys have any recommendation that would fit these dimensions?