I know it's stupid cause you guys could break up and it can end bad mass text gets sent only the girl is labeled a hoe cause that's just how it goes but if you want to try go for it it's your relationship.
Some girls are comfortable with it some not. Just make sure when you bring up the idea to be sensitive to her feelings if he's unsure about it or not to keen on the idea. It really depends on how she sees herself and how comfortable she is with it. Make sure to tell her how beautiful she is!