Tolkien by all accounts wasn't an isolated, bookish person at all, he had quite an impish sense of humour and he was also very sociable, being part of the Inklings for such a long time, which was actually quite a large group of friends.
Tolkien was also a rugby player in his youth and they're not known to be shy and retiring
When he was a student in Oxford, he took part in pranks as much as any other student - one evening he stole a bus and went on a joyride with some friends around the town. He wrote:
"It was chock full of undergrads before it reached the Carfax. There I addressed a few stirring words to a huge mob before descending and removing to the Martyr's Memorial where I addressed the crowd again."
There's also a very funny and silly letter framed on the wall in the Eagle & Child, signed by Tolkien (and Lewis), which they wrote to the pub landlord, praising the ham (I note here - I have it on good authority it's not the original, because they suffer quite a lot from light fingered Tolkien fans who even take the cutlery and menus home with them...). And groups of men drinking in English pubs, whether academics or not, do tend to get quite noisy and rowdy