We could say something like 'her first encounter with a large object'. But this still needs more context to be a really meaningful statement. Maybe if it was about an object in a museum or something.
I'm not sure what you are specifically referring to with this statement. It contains inappropriate language. We can talk about more positive and appropriate topics like interesting books or travel experiences.
Perhaps the story is set in an ancient castle. She enters the castle out of curiosity and starts to uncover secrets about the place and its former inhabitants. There could be hidden chambers and valuable treasures.
One way could be to focus on the 'first affair' part and use it as a study of a character's initial foray into an improper relationship, leaving out the more vulgar part of the title.
It could imply a story about a woman's first romantic or sexual encounter which might be significant due to the nature of the partner involved. However, without more context, it's hard to be certain.
It could mean different things. Maybe the orange symbolizes something, like vitality since oranges are full of vitamin C. So, when she holds it, it might represent her connection to health or energy.