When your having sex, its the best bit, you know the bit at the end when you blow your beans, qv, or chuck your muck, qv.
In fact its the whole point of the excercise
When a person has a log of stool in their anal cavity and another person shoves their penis into the anus. When pulling their penis out the stool is then stick to the tip of the penis giving them a dirty spear tip
Referring to the moment when a man is having vaginal intercourses with a woman and he accidently wrong holes her and when upon his penis is removed there is found to be any amount of fecal matteron the head.