Plush Bottle Holder Pillow, Hands Free Bottle Holder Feeding Assistant, Ergonomic Bottle Support Cushion, Soft Animal Cover Protector, Machine Washable (Pink)

As you say, skip the "let's not prop" - you already know the risks. If you're doing it anyway, we used something like this (and our girls survived just fine and are off bottles entirely now) https://a.co/d/0c3LibXE