to also pee on the grass? He pees on the pads but when I take him outside he just kinda sniffs around and hops in the grass like a bunny

I tried putting a pad out there, but he just hops off of it, cause it probably feels weird especially if the grass is long, he kinda sinks into the pad..loool..So how can I get him to pee in the grass? Coco pees a million times in the grass so I thought he would follow suit. He's 6 months old right now.