When large numbers of people engage in oral sex in alternating face up/face down positions forming a circular group of people. An individual engaged in daisy chaining will be giving oral sex to one person while receiving oral pleasure from a different person (at the same time). Probably referring to a ring of intertwined bosies having a similar shape and arrangement to a flower arrangement used as a tiara.

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British teenagers engaging in a form of group sex The practice involves teenagers going to each others' homes to engage in sex with multiple partners.

when (usually boys in private schools) gather round and toss each other off