EXAMPLE 1:
X: "Yeh, he put loads of gravel in my running shoes so I lost the year group race..."
Y: "That's just bastardic!"
EXAMPLE 2:
X: "I spent the entire night whining about Tommy. He really annoys me."
Y: "He's your best friend! You can be quite bastardic at times, y'know that?"
One who either plays practical jokes on another, or who is just an annoying bitch. The word is typically used to berate a personal friend for doing something to you. I.E., if a friend shits on your chest, he or she is, by definition, a bastardcock. He or she is also fucked up. Really fucked up.
Don, why'd you cream in my eye? You fucking bastardcock.