Have I found a bug or do I not understand the skill (totally possible)

I'm playing scrub league getting my ass handed to me by Dominus when I snag a Curse On Hit skill gem. It doesn't say whether it curses when I hit something or I get hit but I decide to give it a try and link it to my Elemental Weakness Curse skill gem.

I can no longer cast Elemental Weakness which I understand due to the skill but I don't curse when I hit or get hit either. Is this a bug or ???

If not, please help me understand how Curse On Hit works. Thanks!

You need to link curse on hit to your attack so lets say duel strike linked with curse on hit linked with ele weakness. When you then strike an enemy with duel strike it also gets cursed.

I understand now. Thanks!

Yeah, it's a pretty stupid gem. It should work the way you intuitively want it to work but in its current state it's completely useless.

put the payload on a secondary attack. i like using dual curse ball lightning or quality lightning strike on melee

They recently buffed the chance to apply a curse with Curse on Hit to be 100%, so it's massively more useful now. Its main use is if you have 2+ curses to apply, seeing as at that point cursing entire mob packs tends to actually make it take longer to kill them than not cursing, since you spend half your time just on the curses. What you want to do is something like Curse on Hit + SpellWithGoodAoE + Curse1 + Curse2. Not really sure what the best spell in that case would be, Ball Lightning isn't bad, but you'd really want to use it with Greater Multiple Projectiles if you plan to curse, maybe try Ice Nova or something. Either way, you want some sort of AoE so you can curse an entire pack twice in a single hit, at that point it becomes better than manually cursing, if you can afford the links on your gear.

I'll try to get it to work with Firestorm + Elemental Weakness + Curse On Hit + 29% Chance to Ignite + 42% Increased Burning Damage once I get enough links. It's one of my best spells so far even without the curse and it will be nice to curse automatically. Thanks everyone for the info!