An insertive partner is usually someone who inserts their penis or a sex toy into a receiving partner during sex. The term insertive partner usually identifies a person’s role in anal or oral sex. It is most commonly used in the LGBTQIA+ and BDSM communities.
The term is often used interchangeably with the word top. However, insertive partner is a clearer term. That's because it makes clear the person’s sexual role isn’t linked to their physical position during sex. Insertive partners can lie under their receiving partners. The word top does not make this clear.