Pupils at Manor Junior School in Fernhill Road, Cove, were put through their paces by wing forward Eddie Halvey, prop Neal Hatley and London Irish community officer Erin Shardlow.
The trio got the ball rolling by getting a class of seven and eight-year-olds warmed up before explaining the basics of tag rugby.
"Judging by the enthusiastic response from the children, time ran by far too quickly and soon the next class, which had been practising interview techniques, was ready and waiting for their turn," said London Irish spokeswoman Louise Gilsenan.
"At the end of the class, the players were treated to Manor Junior School's own version of the haka, with enough feeling to almost put the frighteners on even seasoned campaigners such as Eddie and Neal!
"The next two classes were of ten and 11-year-olds, who were told all about the importance of keeping a healthy heart.
"Each child had their heart rate taken before going outside where Eddie put them through their paces to show how healthy exercise increases the pulse rate.
"Measurements were then retaken to find their resting heart rate and to see how long it would take for their rates to return to normal.
"All in all, the day was judged to be a great success as it gave the teachers and children alike an invaluable opportunity to gain a first hand insight into the sport."
Schools who would like a visit from London Irish players can contact the community department on 01932 783034.