You are not at risk from this particular situation. It seems likely that you are starting to engage in sex. It would probably be a great idea to keep protection around so it is there if you need it! Take care.
I can't imagine enough sperm getting to your vagina in this manner. A good glob of semen would be necessary before you start to worry. Do you know about the fertile window? Google that to find out more, and download a period tracking app so you understand better your high risk days.