What is it?
SPH is not this.
Small penis humiliation or SPH is “A domination fetish where a man is subjected to comments & gestures about the supposed inadequate size of his penis, & because of such his inability to please a woman, which implies his worthlessness as a man.”, according to Urban Dictionary.
How is it done?
Usually through a cam session or through video. An important aspect of the humiliation is to use terms that describe the penis and its size. Some examples would be: baby carrot, baby cock, baby d, baby dick, Baby Dick Syndrome, Baby Dicked, Baby Weiner, babydick, button dick, dickette, dicklet, dickling, gherkin, Gherkinson’s Disease, Inch Worm, LDL, little chode, little d, little dick, little pecker, Little Peen, Little peeps, little penis, little wee wee, little wiener, maggot dick, Micro Penis, minidick, mini weiner, needle dick, one inch wonder, peenie, pindick, Runt Dick, short dick man, short dicked, short dizzle, short man Johnson, Short Shaft, short stick, small cock, small dick, Small Dick Man, small package, small penis syndrome, small weiner, small-cock, small-dickedness, Teenie Weenie Peenie, tiny, tiny cock, tiny dick, tiny hiding cock, tiny little pecker, tiny little weener., tiny member, Tit Dick, and wee wee
Tips: I recommend watching videos for some inspiration. Example