A phrase used scornfully & contemptuously to someone who keeps making their interest in a subject or person especiallyapparent.
Can be - and often is - shortened to HYH.
Guy: Atsuko is so hot! Have you seen her new character designs? They're really hot. Don't you think Atsuko is the most hot? She is. She's the hottest, Atsuko.
James (rolls eyes): Hide your hard-on, mate.
Guy: Don't you guys love Sakura Wars? It's so cool.
James: Yeah...it's OK. We were actually just discussing British escapes from Colditz.
1) to laugh so much that your dick gets hard
2) to get a hard-on or erection from a dirty or kinky joke
Acronym: LYDH
Pete: This joke will really Laugh Your Dick Hard.
Pete: How do rednecks tell if a girl is old enough to marry?
Joe: I don't know.
Pete: Stand her in a barrel. If her head is above the rim, she's old enough. If it isn't above the rim, cut the barrel down a little.
Joe: HA-HA-HA