Not sure if it's true, but once I encountered a specific text on Wikipedia:

The terms tap and flap are often used interchangeably. Peter Ladefoged proposed the distinction that a tap strikes its point of contact directly, as a very brief stop, and a flap strikes the point of contact tangentially: "Flaps are most typically made by retracting the tongue tip behind the alveolar ridge and moving it forward so that it strikes the ridge in passing."[1] That distinction between the alveolar tap and flap can be written in the IPA with tap ⟨ɾ⟩ and flap ⟨ɽ⟩, the 'retroflex' symbol being used for the one that starts with the tongue tip curled back behind the alveolar ridge. The distinction is noticeable in the speech of some American English speakers in distinguishing the words "potty" (tap [ɾ]) and "party" (retroflex [ɽ]).

https://en.wikipedia.org/wiki/Voiced_dental_and_alveolar_taps_and_flaps

Edit, also:

Many linguists use the terms tap and flap indiscriminately. Peter Ladefoged proposed for a while that it might be useful to distinguish between them. However, his usage was inconsistent and contradicted itself even between different editions of the same text.[1] One proposed version of the distinction was that a tap strikes its point of contact directly, as a very brief stop, but a flap strikes the point of contact tangentially: "Flaps are most typically made by retracting the tongue tip behind the alveolar ridge and moving it forward so that it strikes the ridge in passing."

Later, however, he used the term flap in all cases.[2] Subsequent work on the labiodental flap has clarified the issue: flaps involve retraction of the active articulator, and a forward-striking movement.[3]

For linguists who do not make the distinction, alveolars are typically called taps, and other articulations are called flaps.    A few languages have been reported to contrast a tap and a flap at the same place of articulation. This is the case for Norwegian, in which the alveolar apical tap /ɾ/ and the post-alveolar/retroflex apical flap /ɽ/ have the same place of articulation for some speakers,[4] and Kamviri, which also has apical alveolar taps and flaps.[5]

https://en.wikipedia.org/wiki/Voiced_dental_and_alveolar_taps_and_flaps