Tyra uses her slave as human furniture with two functions, he is her seat and ashtray, two in one ;-)
She sits on his throat first in schoolgirlposition and smokes a cigarette and uses his mouth as ashtray, sitting on his throat, his head between her tighs gives her good control over her ashtray-furniture.
Later she streches her legs for more comfort... her comfort, not his, because with streched legs her full weight comes on his throat, breathing is more difficult, reaction is more gasping for air...
A gasping ashtray ;-)
Julia-Eva decides to teach her slave for beeing a good human stool, for this he has to train his ability to support her weight.
This time she treatens his chest and ribcage under her heavy ass.
His chest is her stool and she sit on it in various positions, letting him to learning to support her.
After some minutes she thinks she must get heavier, she grabs two 5 kg dumbels and sits back on him.
Now, with more weight, the pressure to his chest is higher and the breathing gets more difficult....
More pain > more training-effect!