dickful thinking
A pun on "wishful thinking," it's when a man lets his own sexual interest in someone strongly color his judgement regarding the person's reciprocal interest in him. It makes him interpret every gesture from his object of interest as a come on, even when it clearly isn't. This is known as clitful thinking if it's a woman.
Example:
Him: "So the new hot intern says 'good morning' to me when she comes in to work, and once commented on my desk picture of my kids - said they were cute. She's totally into me. I'm gonna try and hook up with her at the office party."
Friend: "I get that it's been tough for your after the divorce, but that's just dickful thinking. She's not into you, now stop before you get an HR complaint."
OR
Him: "Pete high-fived me at the trivia night - I'll bet he's secretly gay and would let me blow him."
Friend: "You have no gaydar and a bad case of dickful thinking. The boy's straight."
Him: "So the new hot intern says 'good morning' to me when she comes in to work, and once commented on my desk picture of my kids - said they were cute. She's totally into me. I'm gonna try and hook up with her at the office party."
Friend: "I get that it's been tough for your after the divorce, but that's just dickful thinking. She's not into you, now stop before you get an HR complaint."
OR
Him: "Pete high-fived me at the trivia night - I'll bet he's secretly gay and would let me blow him."
Friend: "You have no gaydar and a bad case of dickful thinking. The boy's straight."