Sentence:  One of the most challenging of male sexual disorders is that of delayed <WSD>ejaculation</WSD> (DE). The man who cannot readily ejaculate either alone or, most typically, with a partner, feels thwarted, anxious, and sexually incompetent. 
Meaning of the word marked with <WSD> tags:  A reflex in human beings and other mammals in response to sexual stimulation involving the forcible ejection from the urethra of, in males, semen; and, in females, vaginal fluid.