I'm going to need an example for your edited to add so that I can laugh too. Also I can see why you would get tired of typing the same body part or bodily fluid over and over again. 
Presenting a list of Google's synonyms for body parts and fluids:
penis: phallus, (male) member, (male) organ, sex, erection, pee-pee, mickey, lunch box, intromittent organ, membrum virile, virile member, nerve, person, propagator, tarse, verge, pizzle, loom, needle, pillicock, pintle, runnion
breast: mammary gland, mamma, bosom(s), bust, chest, boobs, knockers, boobies, bazookas, melons, jubblies, bubbies, orbs, globes, bristols, charlies, baps, bazooms, casabas, chi-chis, norks, dugs, paps, embonpoint
butt: buttocks, bottom, cheeks, hindquarters, haunches, rear, rump, rear end, backside, seat, derrière, Sitzfleisch, nates, behind, sit-upon, stern, BTM, tochus, rusty dusty, bum, botty, prat, jacksie, bahookie, fanny, tush, tushie, tail, duff, buns, booty, caboose, heinie, patootie, keister, tuchis, bazoo, bippy, batty, rass, fundament, posterior, breech
vomit: sick, vomitus, ejecta, puke, spew, technicolor yawn, liquid laugh, pavement pizza, barf, upchuck, chunder, purge, parbreak
feces: excrement, bodily waste, waste matter, ordure, dung, manure, scat, excreta, stools, droppings, dirt, filth, muck, mess, poo, doo-doo, doings, turds, caca, cack, whoopsies, jobbies, poop, night soil, egesta, feculence
Those are the best ones I found.
(And yes, my sense of humor is about as mature as my 9-year-old students.)
Oh, I know one that I do so much, it's abysmal. "So-and-so clenched their fist." I don't know why I wrote "so-and-so," it's usually Nick. "Nick clenched his fist." "Nick's clenched fist shook violently." "Nick growled and clenched his fist." [An aside... Yo, they're demons; I figure they can actually growl like dogs. And I hope that when I've written it, anyone reading has read it as "*growling sound* I'll murder you!" because that's exactly what I meant rather than "A rough and gravely voice shouted, 'I'll murder you!'" (Though people growling dialogue would be another one in general, probably, but that's not what I'm focusing on.)] By definition, a fist is a clenched hand! It's so stupid. But "balled his hands" sounds so lame. And I could use hundreds of words that show he's angry (and often do as well), but in the movie in my head, he's ready to punch 90% of the time, so y'all should know that too. I don't have a good solution for this one. I 100% know that it's bad and I do it abundantly.
I get what you're saying, but "clenched" sounds so much better than "made a fist" or "balled his hands." Clenched is more powerful and descriptive; it shows anger and frustration. To me, that makes up for it being a bit redundant. You could always say he "clenched his hands into fists" instead.
