Hi masya ~
I'm sorry I didn't see your message soon after you posted it.
How is your gecko doing?
What you describe is a prolapse. More than likely this prolapse will require a vet & stitches to keep the organs inside.
To stop this bleeding apply direct pressure to the vent area. Hopefully direct pressure will stop the bleeding.
"If you are unable to get the hemipenis to retract at home, keep it moist with a clean cloth soaked in warm water OR apply some vaseline or another lubricant. Your exotics vet may have to sedate your reptile to retract the hemipenis, use a stitch to hold it in place, or even amputate it if it will not go back in and stay in."
Where do you live? Some places have more vet resources than others.
What kind of gecko is this?