Top and bottom
'Top and bottom', 'active and passive' or 'pitcher and catcher' (US) describe a guy's preference to fuck (penetrate) or be fucked (be penetrated) during anal sex. Some guys are versatile, meaning they enjoy both fucking and being fucked. Importantly though, some dislike these labels and prefer to go with the flow.
What you prefer is usually determined by the pleasure you have learnt through experiment and practice. We suggest you keep an open mind and go into sex without a pre-determined idea of what should happen, and then you will likely fall into your natural preference... which may also change over time.
Some men think that in order to be a top you have to masculine and manly while others think a bottom has to be passive or effeminate. This is bollocks. There are so-called masculine looking guys that roll over as soon as you wave your dick in their direction, and so-called passive looking guys that will fuck you into the floor. Fantastic! Just be the man you want to be, with the man you want to be with, ensuring the sex you have is safer, sane and consensual.
For a tad more, read bottom shaming below.
In BDSM, however, top and bottom roles are usually more defined.
This boy is a bottom | GMFA
How to survive being a bottom | GMFA
This boy is a top | GMFA
What happens when you're both tops? | GMFA
Top, bottom and versatile | Wikipedia
Looking beyond gay tops and bottoms | HuffPost Gay Voices | 16 Jun 2013
Every gay guy needs to bottom | Davey Wavey | 31 Mar 2011 2m28s
Am I a top or bottom? | Davey Wavey | 25 Jan 2015 2m59s
Gay men and bottom shaming | Matthew J Dempsey | 14 May 2015 3m48s
BDSM | MEN R US ↑ Back to top