We have a feeling that there might be more to this story than we're being told. When Vanessa Hudgens wanted to shake off her 'Disney' image, she took a part in 'Spring Breakers' precisely because it would call for love scenes and other adult content, thus divorcing herself from the squeaky-clean image of her past. It sounds like something went wrong on set, and she didn't enjoy it.
Hudgens' character got down and dirty with James Franco's in the script, and Hudgens found the experience both nerve-wracking and stressful, to the point where she told her agent to reject any offer that required her to shoot similar scenes. If it was just a case of feeling awkward, then that's fair enough, but she's also enigmatically said that she'd rather 'kiss a girl' than kiss Franco again. It sounds like the issue might be more with him than with the scene.