"用手摸摸看" can be translated into English as "Touch it with your hand to see/feel."
Alternatively, depending on the context and desired tone, you could also say:
"Feel it with your hand." （更简洁）
"Try touching it with your hand." （更委婉或建议的语气）
The first translation ("Touch it with your hand to see/feel.") is the most direct and commonly used in everyday conversation.