Don’t tell her you want it for her. We know that is not true. You are the one obsessed with it so go for a do it for me approach not a I want it for you one. If she loves you like no other, she will do it for you. Also I feel the main female concern is how is our man is really going to react after? Are you going to be upset in any way because any reactions other than loving supportive is BS for doing something you wanted. So if you have shown that you are jealous, insecure, vindictive, quick to anger or might use it against her after you will have a real uphill battle in convincing her to try because she already knows you are probably not man enough to handle it. So you will need to convince her that you will be supportive and not throw it in her face ever, you won’t be upset or jealous or angry. If you use it against her once you can kiss that goodbye forever (and you will want it again) and maybe you just ruined your relationship too. But the this might ruin our relationship not make it better is why most women tell their man “no fucking way”, Because if you thought we are scarred to fuck a hotter guy with a bigger cock, I got news for you, it’s not that