abnormal copulatory plug deposition failure of copulatory plug deposition 2019-09-30T09:51:50Z failure of mating plug deposition absent copulatory plug deposition absent mating plug formation failure of vaginal plug formation MPheno.ontology This term should be used when the cause is either behavioral or unknown. MP:0030983 absent vaginal plug deposition inability to initiate and/or complete the deposition of a plug of sperm or other gelatinous material into the opening of the vulva by a male at the termination of copulation failure of mating plug formation absent mating plug formation