I masturbated next to my girlfriend, and she felt some semen fell near vaginal opening. On realizing, she put the same finger she discovered the semen with inside to check if anything else was there. There was no semen inside. She then rinsed the vaginal opening 4-5 times. I want to know if she could be pregnant, and what can be done right now to avoid it. The incident happened on 29th August 2018.