It is when the man has the girl laying face up on the bed and starts to cuff both her hands to the bed so she can not move (which is considered the web) and then he starts provide a litttle saliva as he is kissing her inner thigh (she will feel a tingle going up her spine) and then he spreads her legs and starts to eat out her pussy.
"dude, she was so horny last night that she wanted me to give her the Black Widow"
A sexual act where a man ejaculates on a womans hands. The women then tells the men to close his eyes. She then proceeds to throw his ejaculation like a web from her hand (taken from the Spiderman) and then hits his balls. She then runs away and leaves the man webbed and in pain.
"In return for her receiving a Spiderman from her boyfriend the night before, she gave him the Black Widow with a quickness"