Question about Dragon Spirit of White

[Bojack]

I just got done with a ranked duel. During the dual, my opponent had three face-down trap/spell cards and I wanted to at least clear out at least one of them before I tried attacking. So I summoned a Hieratic Dragon of Nuit and equipped it with a Tyrant Wing. I did this to special summon a Dragon Spirit of White from my hand so I could active its ability and banish one of his spell/trap cards. So I summoned it in face-up defense position. However, it told me I missed the timing for activating its ability? That's happened to me a few times when I have summoned it from the graveyard or my hand using various stuff. I won the dual anyway. But I can't figure out what's causing its ability to not work sometimes. Any help/advice would be great.

[DUBINA]

Originally posted by Bojack:

I just got done with a ranked duel. During the dual, my opponent had three face-down trap/spell cards and I wanted to at least clear out at least one of them before I tried attacking. So I summoned a Hieratic Dragon of Nuit and equipped it with a Tyrant Wing. I did this to special summon a Dragon Spirit of White from my hand so I could active its ability and banish one of his spell/trap cards. So I summoned it in face-up defense position. However, it told me I missed the timing for activating its ability? That's happened to me a few times when I have summoned it from the graveyard or my hand using various stuff. I won the dual anyway. But I can't figure out what's causing its ability to not work sometimes. Any help/advice would be great.

it misses the timing because it was summoned before tyrant wing effect was resolved. card with "when" in the text and an optional effect "you can" need to happen at that same moment or else its missing the activation timing. like dont chain silver cry when you or opp use a card, since its not a part of a chain and needs to wait for its turn to activate effect.