As the title says, all you can see here are manga's featuring couples with huge, big, age gaps.
Warning: Some of them may feature 'shotacon' (the counter part of lolicon). Doncha worry, I will indicate if ever one has that. *wink*
(Rest assured that I have read all the manga in this list, and thank you for trusting my reviews/comments about them)
Trivia: Psychology says, to find out the minimum age of your 'socially acceptable' lover, you could try to divide your current age by 2 then add 7. Any age less than the outcome will be considered as a 'huge age gap'. (I think I will follow this 'rule' in making this list, but if I feel like a manga belongs here I'll add it even if it's against the 'rule'.)
Hot men being pegged/fingered by ladies [1~65]
Female dominance: reversed roles of that would “normally” be viewed in Hentai [66~…]
= submissive ML - = strong FL
WARNING
■ BDSM stereotypes (usually nocon/dubcon) and/or smut fantasy
■ Depictions of death/violence/torture, rape/nocon, sexual harassment/blackmail/kidnapping,
cross-dressing, Yuri/GL smut, futanari (hermaphroditism/unusual genitalia),
and anything else disturbing