110 mm Soil Pipe Separation

[Poisonata]

Two lengths of 110 mm pipe in my loft (see photo of exact pipe) used as ducting for bathroom fan > outside. Simply push fitted together. Pulling/twisting them apart is proving tricky as the rubber internal gasket at the join is obviously doing its job well. Any thoughts on how this can be achieved relatively easily. I thought about a little spray of silicone down the outer sleeve. Anyone got a quick tip on a better solution.
Thanks in advance.

 

[dilalio]

Grip male end of pipe between knees and trainered feet and Block of wood and a hammer on the female rim of the fitting and tap it away from you.

 

[Poisonata]

That sounds like a plan. Thank you @dilalio