Two men who pinched a woman on the bottom before launching a "vicious" attack on a friend who tried to defend her have been jailed.
Alin-Ionut Apostu, 19, and Alexandru Mocanu, 35, left the victim "lying in a pool of blood" after the assault in Lincoln city centre.
Both men admitted sexual assault and grievous bodily harm.
At Lincoln Crown Court, Apostu was jailed for five years and four months, Mocanu for four years and eight months
The court heard trouble started on the city's High Street in the early hours of 2 December as the victims were walking home.
Romanian nationals Apostu and Mocanu pinched the woman's bottom as they walked past.
Barnaby Shaw, prosecuting, told the court Mocanu punched her friend repeatedly in the head after he challenged them about it.
"Apostu joined in pulling the man to the ground, punching and kicking him and stamping on his head," Mr Shaw said.
"Mocanu also stamped on the man, leaving him lying in a pool of blood."
The court heard Apostu kicked the woman in the head when she tried to stop the attack, before "pulling up her skirt and fondling her buttocks".
"He then kicked her in the head again and spat on her," Mr Shaw said.
Apostu also "karate kicked" another young woman in the head after she tried to help, the court was told.
Recorder Graham Huston, passing sentence, described the attack as "vicious" and "revolting".
"The man made it clear to you that you had just sexually assaulted his friend. You then quite gratuitously decided to attack him," he said.
"He was on the ground unable to defend himself. He was kicked to the face and head and stamped on..."
Mocanu, of Gibbeson Street, Lincoln, and Apostu, of Hood Street, Lincoln, were also placed on the sex offenders register for seven years.
Apostu admitted two further charges of assault.