Apart from the homosexual theme, the images in shunga depicting anal penetration are scarce. In any case, mutual pleasure seems to be the starting point in the designs depicted below. The first two designs are interesting to compare.
Anal sex, though still largely considered a taboo subject, is gradually gaining wholehearted acceptance across cultures and age groups. Even though vaginal intercourse is still the number one trend since Adam and Eve ate the cursed apple, heterosexual anal intercourse is witnessing a staggering number of internet searches and bedroom participation as well. This supposedly outrageous kink has taken the young demography, especially by the storm.