manual application of lubricant

• 人工润滑,手工润滑

manual application of lubricant的用法和样例：

例句

1. Males who engage in mutual masturbation sometimes find it practical to apply some saliva or artificial lubricant to their penises in order to avoid hurting sensitive penile areas.
   相互从事手交的男性发现，为了避免刺痛敏感的阴茎及其周围性敏感区，对阴茎使用唾液或人工润滑液比较实用。