He always goes to the bar without money, hoping to mooch drinks off his friends.

mooch 是动词，意思是"蹭、占便宜"，指不付出代价就获取别人的东西。在这个句子中，mooch drinks off his friends 表示"蹭朋友的酒喝"，带有占便宜、不付钱的意味。