The 29-year-old second row had been initially overlooked for the clash with the French but Alun Wyn Jones' last-minute withdrawal with a foot infection saw him called up to the bench in Cardiff.
And, while the Dragons skipper relished the chance to play a starring role for his region at Rodney Parade, he is desperate to be wearing Welsh colours at Twickenham a week on Sunday, rather than enjoying a week off with his clubmates.
"I had the bad news on the Tuesday that I wasn't playing for Wales and my reaction was to ask to play to get some rugby," Coombs told the Western Telegraph.
"Glasgow was a massive game for us and I wanted to be a part of it. I'd never had two wins in a weekend before and it was great.
"I was pretty low at the start of last week but rugby is a funny old sport and you just have to pick yourself up and things turned around for me. I would have loved to have been in the starting Welsh team but I was happy to take the late call-up to the bench.
"It's going to be tough (to get into the squad to take on England) because the boys played well against France but I definitely feel that I can do a job coming off the bench. I feel like I can add some impact so hopefully I can get a chance to do that at Twickenham."
With Jones hoping to be fit to face the English and Luke Charteris and debutant Jake Ball performing brilliantly on Friday, Coombs faces a real battle to be among the 23 for the trip to Twickenham but he has always been one for overcoming adversity.
Coombs was a surprise addition to the international ranks when he made his Test debut against Ireland at the Millennium Stadium this time last year but he has missed just one RBS 6 Nations encounter since.
He currently has nine caps to his name having played both games on the summer tour of Japan, although a back injury prevented him from featuring in the Dove Men Series Tests in the autumn when he pulled out of the game against Tonga with a back problem.