The common modern-day meaning of the verb tease is inappropriate here in Mosiah 7:1 since there seems to be no jesting in these teasings. In addition, as pointed out by David Eddington (personal communication, 12 July 2004), one might wonder if the use of the plural here isn’t an error for the singular teasing.
According to the Oxford English Dictionary, the earlier meaning of tease did not imply jesting, thus the OED definition ‘to worry or irritate by persistent action which vexes or annoys’ (see definition 2 under the verb tease). Further, there is the following citation (found under the verbal noun teasing) that shows plural usage with the same basic phraseology as in Mosiah 7:1:
Summary: Maintain the plural use of teasings in Mosiah 7:1; both the meaning and the plural form can be supported from earlier usage in English.