With side sleeping you want your head higher compared to sleeping on your back. Otherwise you'll get neck/shoulder pain because your head bends down too much. My pillow still feels soft, but it's very elastic. I'd say it compresses about a third of its size or less. I can feel my hand under my pillow but there's still some give. I found it on my order history, if it helps:
Beautyrest Talalay Latex Foam Pillow,... https://www.amazon.com/dp/B000BI22UW