I am a male and engaged in mutual masturbation with a male yesterday.  There was no oral or anal sex.  Our penises rubbed against each other.  There may have been pre-ejaculate but there was not much.  When we ejaculated we did not ejaculate on each other.  He had no visible sores, wounds, etc.  I am wondering my risk for STIs is?  I am in a long-term relationship and am concerned about contracting a STI and then sharing it.