‘Let me see three mosh pits! I need the hat-trick!” shouts Aitch, fully aware he could ask almost anything of his teenage Glasgow fans. They scream as if they’ve just hit the drop on a rollercoaster. The Manchester rapper is rounding out an unbelievable 12 months. Aitch – AKA Harrison Armstrong – turns 20 next week and has had three top 10 hits this year, including Taste (Make It Shake) which reached No 2.

Despite the sharp rise to fame, he looks at ease. Strolling up and down the stage, twirling a finger as he raps, Aitch’s deceptively laid-back bars are crammed with 0161 area code in-jokes and sharp tongue-twisters, bringing bags of character to nondescript trap beats. DJ Win, head of the Northern Quarterz talent agency that represents Aitch, bounces next to him, whipping his shirt over his head.

Aitch preaches his work ethic on breakthrough track Straight Rhymez – “Dad says there’s not a lift up to success” – but mostly his tracks are full of teenage innuendo, detailing conquests (“Eat it like a Creme Egg,” he smirks on Weekday) with the hopeful tone of a Christmas wishlist. Croydon rapper ZieZie joins him for their pleasingly naff single French Kisses and stays for Buss Down, a breezy number prefaced with a silly skit about getting the bus to Glasgow.

He describes his 2018 freestyle for the Daily Duppy series as “taking it old-school”, cracking a grin as he nails it – little surprise that last year feels a lifetime ago for the rapper – and he jumps straight into his “Manny”-repping verse on Stormzy and Ed Sheeran’s Take Me Back to London remix. Taste (Make It Shake) would have been an easy and triumphant closer, but instead he opts for the low-key single Wait, suggesting that for Aitch, it’s all still to play for: “I won’t let it go to waste, trust me.”

• At Concorde 2, Brighton, 10 December. Then touring until 19 December.