Thank you for your query at Doctorspring.com
I understand your concern.
I have gone through your complete exposure history and I can assure you, you won't get any STI from just bathing and touching of the testicles or butt crack with her fingers.
You do not need any testing. As long as no intercourse or oral sex involved, you're safe.
Hope this was helpful,
Patient replied :
Dear Doc ,
thanks for your Reply . i am bit relieved . as per your advise i will put this behind me and move on .
You can definitely move on.
All the best!