Straight: Alice hugs Bob. Bob ejaculates prematurely as a result of this.
Exaggerated: Bob ejaculates when he sees Alice fully-clothed from ten feet away.
Alice and Bob are making out and Bob ejaculates a bit after getting to second base.
Bob enjoys being hugged by Alice to a somewhat suggestive degree, but it doesn't seem like he had an actual orgasm.
Justified: Bob has a medical issue that causes him to ejaculate prematurely.
Inverted: Bob can hold out for hours during sex.
Subverted: Something exploded in Bob's pocket.
Double Subverted: This is his lame excuse.
Parodied: There is a blast like a cannon; Bob's crotch is seen smoking.
Zig Zagged: Something exploded in Bob's pocket. This seems to be his lame excuse. He pulls out the ruined item, still leaking its fluid. Then there's a reason why it couldn't have possibly come from that particular trinket, so it must have come from his other one...
Averted: Nobody ejaculates onscreen.
Enforced: The work is an ad for a product designed to help men last longer.
Invoked: Alice gives Bob a lap dance.
Defied: Bob has a condom on before he arrives at Alice's place, or is taking medication or other precautions.
Discussed: "I swear, if she did that to me, I would come right here in my pants."
Conversed: "What real person has that little self control?!"
Bob becomes socially ostracized.
Bob loses a girlfriend.
Reconstructed: Bob's girlfriend deliberately teased him to that point with no-one else around.
Played For Drama: Bob loses, or has to fight hard for, a relationship because of it.