Tengu format ruling
Drastic Drop Off

Card effect (current official text)When your opponent adds a card(s) from their Deck to their hand, including drawing: They must discard 1 of those cards.
Rulings
- If your opponent discards card(s) after drawing or adding card(s) to their hand as part of the same effect resolution, you cannot activate Drastic Drop Off. For example, when your opponent resolves Graceful Charity, you cannot activate Drastic Drop Off.
- If you're the one using this card, tell your opponent that you might want to activate an effect before they shuffle the drawn card into their hand. Also ask them if they wish to activate anything before you do.
- If Destiny Hero - Dasher is in your opponent's GY, and you have a Set Drastic Drop Off: when your opponent draws a Monster Card during their Draw Phase, they can activate Dasher's effect (as Chain Link 1). However, you can chain Drastic Drop Off to discard the Monster Card they drew.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.