I would say talk to her see how she feels about it. I can understand feeling bad if she is truly uncomfortable doing it. I feel bad when I get my girlfriend in the eye now so sometimes I will have her wear her glasses or sunglasses. It adds a bit of safety and another layer of fun. So if she has a hard time with certain aspects like getting in her eyes or gagging if it goes in her mouth funny you can try and find a way together to make sure both people are happy. But the key is communication.