A person who performs fellatio; one who engages in oral sex involving the penis.
From Latin fellare (to suck) plus the agent suffix -or (one who does), following the Latin pattern for creating agent nouns that became standard in English.
Fellator is the traditionally 'masculine' form in Latinate grammar, but modern English uses it regardless of gender—showing how old grammatical systems don't match modern understanding of sexuality and identity.
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