If Henshin Dekinai and Okane ga Nai were relationship advice manuals, Okane ga Nai would be what NOT to do while Henshin Dekinai would be things you SHOULD do (such as ask for consent)...
If Henshin Dekinai and Okane ga Nai were relationship advice manuals, Okane ga Nai would be what NOT to do while Henshin Dekinai would be things you SHOULD do (such as ask for consent)...