How does the mattress topper fit on my mattress? January 29, 2021 19:03 Both the plush and firm mattress toppers are skirted and will fit snugly over your mattress like a fitted sheet. Related articles Who is eligible for a complimentary mattress topper? How much of a difference will the Mattress Topper make? Will I be charged for the mattress topper if I return my Helix? Can I wash my complimentary topper? What is the Helix Mattress Topper program?