Sub-umbra, or sport among the she-noodles is a classic Victorian erotic novel, published in 1883. It contains graphic sexual descriptions and themes.

“Do you never think of love, Annie? Look me in the face if you can say it’s a stranger to your bosom,” putting my hand familiarly round her neck till my right hand rested on one of the panting globes of her bosom.
She turned her face to mine, suffused as it was by a deeper blush than ever, as her dark blue eyes met mine, in a fearless search of my meaning, but instead of speaking in response to this mute appeal, I kissed her rapturously, sucking in the fragrance of her sweet breath till she fairly trembled with emotion.
It was just beginning to get dusk, my hands were caressing the white, firm flesh of her beautiful neck, slowly working their way towards the heaving bubbies a little lower down; at last I whispered, “What a fine, what a lovely bust you have developed since I saw you last, dear Annie, you won’t mind your cousin, will you, when everything used to be so free to each other; besides, what harm can there be in it?”
She seemed on fire, a thrill of emotion seemed to shoot through both of us, and for several moments she lay almost motionless in my arms, with one hand resting on my thigh. Priapus was awake and ready for business, but she suddenly aroused herself, saying, “We must never stop here. Let us walk round or they will suspect something.”