When you are haveing sex with a girl and you pull out and nut in the palm of your hand. You then throw the jizz at her face like the web of spider man.
Dude that bitch wouldnt let me nut on her face. So i Spidermaned that ho.
The act of ejaculating into your hand, then positioning your fingers with your thumb, index, and pinky pointed out; and your middle and ring finger curled under (as spiderman does when he shoots his web), then flinging it in the face of your partner.
After fucking a chick in the ass. You pull out and cum in your hand. When she turns around you throw the cum in her face like a spider web. Then yell "look out for SPIDERMAN"!!!
a sexual exposure in which just before climaxing you yell "MY SPIDEY SENSES ARE TINGLING" and then blow in her face while using the spidey hand slinging motion as if you were casting out a web over her face.