The "Yondu" refers to the outcome of a rather kinky sexual situation. The chain of action to achieve a Yondu status goes as follows. To start with you take a girl who is on her period to the bathroom. As soon as you get a hold of the blood-soaked tampon you smack it on the tiles making it stick to it. Then the guy shoots a load of semen on it acting as the adhesive agent. With the help of a confident movement from the guy holding the back of the girl's head, the tampon gets glued to the forehead. The last step of becoming Yondu is being able to deliver a constant blow whistle sound while being fingered in her "raccoon" meaning her vagina. If the whistle is satisfactory to the guy she gains full control of his "arrow" meaning his penis in this setup.
-Hey man, what have you been up to yesterday?
-Nothing much we tried something new with my girl and we had such a great time.
-What have the two of you been up to?
-Well I did The "Yondu" with her and we laughed our ass off and kind of spiced up our sex life.
-Glad to hear that man. I`m happy for you to have a girl sharing the same interests with you.
-It blew me away man.