The Shi'a Ayatollah Ruhollah Khomeini defined the following limits and
consequences for adult sexual activity with children (roughly translated
from Arabic):

    "A man can marry a girl younger than nine years of age, even if the
girl is still a baby being breastfed. A man, however is prohibited from
having intercourse with a girl younger than nine, while other sexual
acts such as foreplay, rubbing, and kissing are allowed. A man having
intercourse with a girl younger than nine years of age has not committed
a crime, but only an infraction, if the girl is not permanently damaged.
If the girl, however, is permanently damaged, the man must provide for
her all her life. But this girl will not count as one of the man's four
permanent wives. He also is not permitted to marry the girl's
sister."[1]

Khomeini specifically described an act known as thighing that allowed an
adult male to simulate sex with a female child without penetration:

    "Thighing is a means for an adult male to enjoy a young girl who is
still in the age of weaning; meaning to place his penis between her
thighs, and to kiss her."[2]

#1 Ayatollah Khomeini in Tahrirolvasyleh, Fourth Edition, Darol Elm, Qom
#2 Khomeini. Sayings of the Ayatollah Khomeini: Political,
Philosophical, Social, & Religious Bantam Books:1985. ISBN-10:
0553140329